Abram was promised so many descendants that they would be like the stars in the sky. Abram believed God and that was considered righteousness.
He was getting old, though. He was 86 and his wife Sarai was 76. The had not had any children yet and it did not look like God was going to come through on the promise. So, Sarai gave Abram her maidservant Haggar. He slept with her and she bore him a child. Abram was now going to have descendants.
Thirteen years later, the LORD spoke with Abram about the promise that his descendants would be like the stars of the sky. God renamed him Abraham as a reminder that he would be the father of many nations.
So Abraham said to God, "May Ishmael live under Your special blessing!" But God replied, "No--Sarah, your wife, will give birth to a son for you. You will name him Isaac, and I will confirm My covenant with him and his descendants as an everlasting covenant. As for Ishmael, I will bless him also, just as you have asked. I will make him extremely fruitful and multiply his descendants. He will become the father of twelve princes, and I will make him a great nation. But My covenant will be confirmed with Isaac, who will be born to you and Sarah about this time next year." (Genesis 17:18-21 NLT)
God made it perfectly clear to Abraham. Sarah was going to bear a child at the ripe young age of 90. Don’t try to brush this off as no big deal because they lived longer back then. This was after God limited our lives to 120 years. Having a child at 90 back then was the same as having a child at 90 now. It was impossible. That’s actually the point.
On that very day Abraham took his son, Ishmael, and every male in his household, including those born there and those he had bought. Then he circumcised them, cutting off their foreskins, just as God had told him. Abraham was ninety-nine years old when he was circumcised, and Ishmael, his son, was thirteen. Both Abraham and his son, Ishmael, were circumcised on that same day, along with all the other men and boys of the household, whether they were born there or bought as servants. All were circumcised with him. (Genesis 17:23-27 NLT)
Circumcision was the sign given to Abraham on that day. The removing of foreskin from the male reproductive parts would be a constant reminder. God is even powerful enough to control our fertility. God can make a fertile person sterile and God can make a sterile person fertile. That is exactly what God did with Abraham and Sarah. God did this to show them that God is powerful enough to come through on promises. Sarah had Abraham’s child at the age of 90. He was 100. God has the power to follow through on promises.
How about you? Have you seen God follow through on promises that were “impossible?” How did that affect your faith in God?