God has been dealing with Abram, destined for a name-change in this chapter, by appearing to him five times up to this chapter, with two to follow in later chapters. God tested Abram (Abraham) seven ways, as follow:

God reaffirms His covenant with Abram in this chapter, establishes circumcision as the physical sign of the covenant and changes Abram’s name to Abraham, which reflected one aspect of the Abrahamic covenant. In like manner, in the Church Age, Christians may daily read God’s Word and be reaffirmed regarding God’s New Covenant of salvation by faith alone in Christ alone. They are to submit to water baptism (immersion), which is a sign of the New Covenant. And they acquire a new name, “Christian,” which indicate they are believers in and followers of Jesus Christ.

Abram, now 99 years old, a time when an average person would have concluded that God had either forgotten or retracted His promises (covenant), was again and in person approached by God. At this time God introduces Himself to Abram with a new name, a composite name of the Hebrew words El meaning “God” and Shaddai meaning “Almighty.” In the culture of the time, names and their meaning meant a great deal, often conveying an element or message pertaining to that which was named. By God referring to Himself as “God Almighty,” He was telling Abram that nothing was impossible for Him to accomplish. This was important for Abram to understand, since God was about to reaffirm to Abram that even though Abram was past his prime to have children, He would indeed be blessed with a child by the mighty hand of God.

God tells Abram to “walk before Me and be blameless,” reinforcing the type of conduct He expected of Abram, one of obedience and free of sin—impossible for man then, as it is now; but still, God’s requirement for all mankind. Next, God reaffirms His covenant with Abram—that God would greatly multiply his descendants and that Abram would be “father of many nations.” And to reinforce this aspect of the covenant God changes Abram’s name, which meant “high father” (or “exalted father”) to Abraham, meaning “father of many nations” (or “father of a multitude”).

This element of the “covenant” (a word used 13 times in this chapter) is seen in the two lines of Abraham’s descendants through his two sons, Ishmael and Isaac. These number far beyond man’s ability to count. And no two lines of people have had a greater impact on world events or a greater prophetic impact on the world and its future destiny.

God further declares to Abraham that He will maintain the special relationship established between them (personal and as the one and only true God) with Abraham’s descendants and will also honor His covenant promises with Abraham’s descendants; but His words here, as will be seen later, refer to Abraham’s descendants through Isaac, the nation of Israel. Then God reaffirms that to Abraham’s descendants (through Isaac, the nation Israel) the land of Canaan would be given as an “everlasting possession.” Because of this covenant, the nation Israel has legitimate right to all the “holy lands” today, not the Palestinians.

God next institutes “circumcision” as a sign of the covenant between God and Abraham and Abraham’s descendants through Isaac, a physical sign showing that the person circumcised belongs to God’s chosen earthly people. Abraham, Ishmael and males within Abraham’s household were to be circumcised immediately, and thereafter every male child was to be circumcised upon reaching the age of eight days. God said that any child not circumcised would be “cut off”—that is, put away from the congregation of Israel. Although the expression, “cut off,” can sometimes mean “put to death” in the Old Testament (Exodus 31:14, 15), here it means to ban or ostracize.

It is important to note that Abraham was justified before God before he was circumcised (Genesis 15:6), a fact that did not escape the Apostle Paul. Abraham (under the name of Abram) received the “seal of righteousness,” which only comes by faith, of which physical circumcision was only a sign thereof (Romans 4:11). Believers today are sealed forever by the Holy Spirit when by faith alone in Christ alone they are saved, after which they experience water baptism as the “sign of their faith in and union with Christ.”

In addition to the above remarks, the following selected portions of the research by John D.W. Watts, Th.D., Professor of Old Testament, Serampore College, India, regarding circumcision as stated in the Wycliffe Bible Dictionary, Hendrickson Publishers, 1975, are informative, as follow:

Circumcision was to be performed on a male child upon his eighth day after birth. This commentator recalls from previous investigatory efforts that this time frame, from a medical standpoint, is the ideal time for such a procedure. The reason is that at this time and due to chemical processes within the young boy’s body, the clotting of blood is facilitated. But further medical research should be made to verify this conclusion. Finally, both John the Baptist and Jesus Christ, who were born under the law (Galatians 4:4) were circumcised on the eighth day of their lives (Luke 1:59; 2:21, 22).

God had given Abram his new name of Abraham. He then renames Sarai as Sarah, both names meaning “princess.” God assures Abraham, here at the age of 99, that by his wife of 89 he would be given a male child. Abraham did the math, knowing that upon this child’s birth he would be 100 years old and Sarah would be 90 years old. Upon this realization and because of his great faith in God’s promise, he laughed with joy, not incredulity, as did Sarah when she heard the news later (Genesis 18:12). Abraham’s faith and how God credits righteousness only upon the expression of faith is best seen in Paul’s description of this event (and how it conveys salvation by faith alone in Christ alone) in Romans 4:16-25, as follows:

Abraham did not forget his firstborn through Hagar. He pled with God for his son Ishmael to be included in God’s covenant-promise, but God informed him that His covenant with Abraham would only be fulfilled through his future son, Isaac. However, Ishmael would be blessed by God. Ishmael would be fruitful, would multiply, and would become a great nation. But Isaac, as a symbol of the coming Messiah, was the only one through whom the covenant could receive its ultimate fulfillment. At the termination of the conversation, God went up from Abraham to heaven.

So Abraham took Ishmael his son, all who were born in his house and all who were bought with his money, every male among the men of Abraham's house, and circumcised the flesh of their foreskins that very same day, as God had said to him. Abraham was ninety-nine years old when he was circumcised in the flesh of his foreskin. And Ishmael his son was thirteen years old when he was circumcised in the flesh of his foreskin. That very same day Abraham was circumcised, and his son Ishmael; and all the men of his house, born in the house or bought with money from a foreigner, were circumcised with him.