The practice of circumcision is first mentioned in Genesis 17. Archeologists have found evidence that it was practiced in all Semitic cultures as well as Egyptian cultures, especially among the priesthood. Although the non-Israelite cultures viewed circumcision as a rite of passage (performed at age 13 or even 18), the Israelites attached religious significance, performing the rite when a boy was eight days old. Every Israelite male carried with him a constant reminder of his professed promise of loyalty to God. Circumcision was the special sign God gave Abraham indicating that his descendants would ascend to greatness, acquiring physical and spiritual blessings of inheritance. The spiritual principle is still binding on anyone called into God's family. The descendants of Ishmael have assimilated into the Arab population in North Africa, spawning the violent Islam religion. Through Abraham's, Isaac's, and Jacob's descendants, the world would be blessed with material and political greatness. Circumcision is only an outward sign, largely as a means of identification, setting the Israelite people apart from the rest of the world. Strangers who desired to participate in the blessings of the commonwealth of Israel and the covenant of promise had to undergo circumcision. In order to receive the spiritual promises given to the Israel of God, we are to undergo circumcision of the heart, cleansing the mind from sin. Baptism, in effect, has replaced physical circumcision. Though physical circumcision is not necessary for salvation, it does have hygienic benefits and will be practiced during the Millennium.