It took a total of 25 years for the promise of God to Abraham to be fulfilled. The promise was that Abraham would become the father of many nations through his own son.
Abraham was a Jewish prophet who is most commonly known for having great faith in God. He had a wife named Sarah who was barren, making it difficult for Abraham to have descendants. Due to this predicament, Abraham was forced to take another woman named Hagar in order to leave his seed on Earth. However, God made a promise to Abraham that he would become the father of many nations by having a son with his wife Sarah.
When God made this promise, Abraham believed it, despite being quite old and his wife having attained the age of menopause. After 15 years of waiting for the promise, God visited Abraham again and assured him that the promise would be fulfilled in due time. It took another 10 years after the reassurance for Abraham and Sarah to give birth to a son who was named Isaac. After several years, God tested Abraham's faith by asking him to sacrifice his son Isaac to which Abraham obeyed, but was stopped before he could fulfill it.