God had promised Abraham that he would become the father of many nations, yet, he and Sara did not have a child. They were well past child-bearing age when God delivered on His promise to Abraham. Though, from a human standpoint, it was impossible, it was not hard for God to fulfill His promise. After all, when He speaks, the sound of His voice creates whatever He says. He spoke the universe into existence. So, bringing forth a child from an elderly couple would not be difficult for Him. This promise was passed down from generation to generation. Many of them died before the promise was realized, but they died knowing that God is faithful and He would fulfill every promise. They pressed on in obedience to God and arrived at a heavenly country where they will spend an eternity with God because they were faithful.
“The Gospel has come to you because it’s on its way to someone else.” -Anonymous