By faith Abraham obeyed when he was called to go out to the place which he would receive as an inheritance. And he went out, not knowing where he was going. Hebrews 11:8
Abraham is considered the father of the faith because of his encounter with God and his obedience to take Him at His word and believe. Because he told God he had no heir God promised him that his descendants would be innumerable as the stars of heaven.
God told Abraham that his wife would conceive a son that would be his heir but at the age of eighty six. His wife Sarah didn't believe, and so she had him go into her servant, Hagar and she conceived a son and they named him Ishmael. Ishmael became the father of twelve princes of twelve nations but was not the son that God promised. When Abraham was ninety nine God appeared again and re-confirmed His covenant promise of an heir to be born in his house, and so Sarah his wife conceived and they named the boy Isaac.
The moral to this story is to take God at His word and stand on His promises, no matter what the circumstances He will come through. Because Abraham listened to his wife and his own understanding telling him he was too old he made a horrible mistake, by going into her servant and she conceived the father of all of the Arab nations. We would do well to take this story to heart lest we also birth an Ishmael in our life.
Then He brought him outside and said, "Look now toward heaven, and count the stars if you are able to number them." And He said to him, "So shall your descendants be." And he believed in the Lord, and He accounted it to him for righteousness. Genesis 15:5,6
Your servant in Christ, Tim Laughlin