The apostle John provides insight into the antichrist spirit that was evident at the end of the first century and persists today. He describes many antichrists as individuals influenced by this spirit who have separated from the faithful. John identifies these antichrists as those who deny the Father and the Son, rejecting Jesus Christ as the Messiah.

In his epistles, the apostle John introduces the term antichrist, using it in a general sense to describe an attitude opposed to God and those who embody it. He notes that even in his time, there were many antichrists, individuals influenced by an unholy spirit that led them to beliefs and practices contrary to the Savior. These antichrists had once fellowshipped with the brethren but separated due to the conflict between the unholy spirit and the Spirit of God. John warns the church to remain vigilant, as the antichrist spirit could still deceive those who stayed. John further identifies antichrists as those who deny that Jesus Christ has come in the flesh, countering false beliefs that corrupted the true nature of the Messiah. He emphasizes that anyone who rejects the incarnation of God into human flesh stands against the very purpose of the Messiah's life, ministry, and death. Through these warnings, John urges believers to test the spirits behind the messages they hear, ensuring they align with the truth of Scripture and the reality of Christ's incarnation.

The concept of the Antichrist is a critical element in understanding false teachings and deception within the spiritual realm. John, in his epistles, warns that antichrists are present at all times, with their influence intensifying as the end approaches. This makes it essential to recognize the spirit of Antichrist, which often becomes evident only after such individuals depart from the true path, revealing their divergence through a track record of contrary actions. These individuals, if truly aligned with Christ, would remain among the faithful, but their departure signifies their antichrist tendencies, as they become uncomfortable among those striving to be Christ-like. John defines an antichrist as one who denies the Father and the Son, essentially rejecting or refusing God's truth. This denial can manifest in various forms, from resisting the Holy Spirit's guidance to outright rejection of God, ultimately distorting the true nature of God in one's mind. By rejecting any part of God's revelation, the image of God becomes skewed, leading to a false understanding. God acknowledges human limitations in fully comprehending His nature and offers grace for this shortfall, expecting a sincere effort to grow in understanding. Yet, it must be recognized that elements of antichrist exist within all, stemming from a past immersed in a world opposed to God. Even after being called out, remnants of anti-God attitudes and beliefs linger, requiring continuous effort to purge them with the aid of God's Spirit. The Christian journey is thus a lifelong endeavor to root out the antichrist within, striving to embody Christ's character. This process of eliminating antichrist tendencies aims to transform individuals into reflections of Christ, aligning with God's purpose to create sons and daughters in the image of His Firstborn. The struggle against antichrist elements is fraught with challenges, compounded by human nature and satan's influence. However, the reward for those who persevere, especially in the first resurrection, is profound, promising a closer likeness to Christ and an eternal position alongside God and Christ. The essence of Christian life is to cast out the antichrist and embrace Christ, putting on the new man as a constant act of transformation.

The term antichrist appears solely in I and II John. As I John 2:18 states, little children, it is the last hour; and as you have heard that the Antichrist is coming, even now many antichrists have come, by which we know that it is the last hour. Numerous antichrists existed during the apostle John's time at the end of the first century AD, pretending to belong to God's true church, yet as John notes in verse 19, they went out from us, but they were not of us. An antichrist is defined as a deceiver, according to II John 7, which warns of many deceivers who do not confess Jesus Christ as coming in the flesh. Antichrists deceive by teaching a false, unbiblical Christ, altering the nature of God to fit their own purposes and presenting it as truth. This deception includes changing the gospel, as seen in Galatians 1:6-9, where a different gospel was preached as early as the AD 50s, obscuring the glorious good news of the Kingdom of God and altering the beliefs and hope of those whom God calls to His way of life. Breaking down the word, anti- means against, and Christos refers to the anointed one, Jesus. Thus, an antichrist is one who stands against the true Christ, described by John as a person hostile to true Christian interests, particularly false teachers from within the church who spread error. Additionally, it is indicated that one particular Antichrist will emerge on the world scene shortly before the return of Jesus Christ.

There is a significant focus within Christianity on the concept of the antichrist, with questions surrounding when he will appear, whether he is already present, and who he might be. The apostle John warns in I John 2:18-23 that it is the last hour, and as many have heard, antichrist is coming, even now many antichrists have come, indicating the urgency of the times. He clarifies that these antichrists went out from the church but were not truly of it, revealing their true nature by their departure. John defines an antichrist as one who denies that Jesus is the Christ, thereby denying the Father and the Son, and emphasizes that whoever denies the Son does not have the Father. Further, in I John 4:3, John states that every spirit that does not confess Jesus Christ has come in the flesh is not of God, identifying this as the spirit of the antichrist, which was already in the world during his time. In II John 7, he reiterates that many deceivers who do not confess Jesus Christ as coming in the flesh are antichrists. The term antichrist, derived from the Greek word antichristos, signifies both opposition to Christ and an attempt to stand in His place, often through subtle deception and lies, which are major traits of antichrists motivated by pride and self-righteousness. John notes in I John 2:19 that these antichrists, though once among the church, separated themselves, making it evident they were not of the true believers. This spirit of antichrist has been active since the days of Paul and John, permeating individuals, institutions, and societies, and is expected to reach its peak influence in the years before Christ's return. The spirit of antichrist is characterized by deception, denying the necessity of the Messiah and His mission, and promoting counterfeit solutions to global issues. In Revelation, the spirit of antichrist is linked to figures like the Beast and the False Prophet, who deceive through signs and wonders, leading many astray. The apostle Paul, in II Thessalonians 2:3-4, describes a man of sin, the son of perdition, who exalts himself as God, embodying this spirit. This deception aims to convince the world that Christ, at His return, is the antichrist, a tactic to mislead even the elect. Despite this, Christ will ultimately overthrow these forces, casting them into the lake of fire, ending the rule of antichrist over the nations. John warns in I John 4:1-4 to test the spirits, as many false prophets and antichrists have gone out into the world, but assures believers that He who is in them is greater than he who is in the world. The presence of antichrists within the church serves as a test of faith, challenging believers to stand firm in truth and resist the subtle, seductive power of deception that seeks to lead them astray in this last hour.

According to the apostle John's second epistle, an antichrist is specifically identified as one who denies that Jesus Christ is presently dwelling within His followers, a concept distinct from merely acknowledging His first coming in the flesh. Paul establishes in Colossians 1:27 that Christ in us is the hope of glory, and John connects this indwelling hope directly to purification, since those who hold this hope will strive to purify themselves, as stated in I John 3:3. This purification is essentially the process of overcoming, conquering what defiles, and aligns with Paul's description of perfecting holiness in the fear of God. Because of this, John consistently links Christ's indwelling with keeping the commandments, since these provide the standard by which believers measure themselves, and also with love, since Christ's presence enables believers to treat others as He does. A hope focused on becoming a glorified child of God demands that one's life be centered on removing whatever is not aligned with that end. In II John 8-9, the warning intensifies: those who transgress and do not abide in the doctrine of Christ's indwelling by His Spirit do not have God, while those who abide in this doctrine possess both the Father and the Son. This corresponds to Jesus' words in John 14:23, where those who love Him keep His Word, resulting in the Father and Son making their home within them. The emphasis throughout is on present activity rather than the historical fact of the Incarnation alone. While professing Christians generally confess that Jesus came in the flesh, as required in I John 4:2, most do not accurately confess that He is presently entering or appearing in their flesh, a reality revealed through their works, since they deny Him in practice according to Titus 1:16. This is evident because Jesus dwells in those who keep His commandments, yet most professing Christians reject the necessity of keeping the fourth commandment, the Sabbath. This rejection stems from their lack of the hope of glory, as their hope rests instead in going to heaven and in false doctrines such as once saved, always saved, revealing that they are not led by the same Spirit that motivates believers toward purification in anticipation of what lies beyond the resurrection. Since the Father and Son are one, those in whom they dwell will likewise incline toward unity. Continual animosity and recurring disharmony in relationships indicate the presence of a spirit contrary to the indwelling of the Prince of Peace, a spirit John identifies as antichrist. Through these warnings, several indicators emerge for discerning what is and is not of Christ. The world does not understand the mystery of Christ in believers or the hope of glory, but where this belief is taught, alive, and growing, there will also be growth toward the pure standard, since the Creator is actively creating within those He indwells. Conversely, anyone who comes without this doctrine and practice is, according to John, a deceiver and an antichrist.

The apostle John's warning in I John 2:18-23 forms the foundation for understanding antichrist not as a single future figure but as a spirit of deception that has operated since apostolic times. Rather than satisfying curiosity about identifying one mysterious individual, John's purpose was protective: safeguarding believers' fellowship with the Father and the Son from subtle deception that steals truth and can cost one's crown. The term "the last hour" describes the entire period from Christ's ascension until His return, marked by recurring seasons of intensified conflict, not merely an imminent end. The Greek word antichristos carries two meanings: one who stands against Christ, and one who stands in Christ's place, presenting a counterfeit gospel while claiming His name. Antichrists are characterized by pride, self-righteousness, lying, and denial of Christ—whether by denying His deity (as mere teachers claim), His humanity (as Gnostics taught), or by works that contradict profession, as Paul told Titus. This denial persisted through church history, from early heresies to Catholicism's false intermediaries, Protestant denial of the miraculous, and Judaism's rejection of Messiahship. Even modern human-devised solutions to global problems—political, environmental, or religious systems that exclude Christ's necessary return—embody this same spirit, as does religious syncretism like "Chrislam." John notes that antichrists "went out from us," meaning they arose within the church itself, later exposed by God to true believers possessing the Holy Spirit's anointing, which teaches discernment without needing external instruction. This internal danger parallels Paul's warnings to the Ephesian elders about wolves rising from among the flock, most dramatically fulfilled in the apostasy that fractured the Worldwide Church of God. Prophetically, this spirit reaches ultimate expression in two end-time figures: the Beast, a militaristic ruler over ten kingdoms, and the False Prophet, a miracle-working religious leader who deceives through lying wonders, causing many to worship the Beast's image. Together they will be defeated when Christ returns and cast into the lake of fire. Notably, deceptive religious systems are expected to convince the world that Christ Himself is the antichrist at His return—making obsessive speculation about "who is the antichrist" itself part of the deception, distracting believers from present faithfulness. God permits antichrists to test the righteous, as illustrated in Psalm 11 and confirmed by John's instruction to "test the spirits" (I John 4:1-6). The ultimate response is not fear but steadfast confidence, since "He who is in you is greater than he who is in the world." The call is to remain vigilant, reject error, hold fast to truth, and persevere faithfully until Christ's return overthrows every counterfeit power permanently.