“By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises offered up his only begotten son, of whom it was said, ‘In Isaac shall your seed be called’, concluding that God was able to raise him up, even from the dead” (vs. 17-19).
There are times in life when what God asks of us doesn’t make any sense. Why would God perform a spectacular miracle in giving Abraham and Sarah this “promised son” when it was humanly (biologically) impossible, only then to take him away from them? It is hard to trust the Lord when you don't understand what the Lord is doing! But that is when faith is really needed--when we can't figure out His plans and purposes--when nothing seems to make sense.
Abraham’s obedience to God was based on the truth that if God gave him Isaac once, He could give him back a second time by raising him from the dead! Abraham’s faith rested on the resurrecting power of God. Hebrews 11:19 says: "concluding that God was able to raise him up, even from the dead". The truth of the resurrection is truly at the core of our Christian faith, the cornerstone of all that we believe.
Abraham’s great faith was passed down to Isaac (vs. 20), Jacob (vs. 21) and Joseph (vs. 22). That ought to be an encouragement to every Christian parent-- that your legacy of faith can and should be passed down to your children and grandchildren. The Covenant promises of God to Abraham were repeated to each succeeding generation. The most important thing we can do for our children and grandchildren is to make sure they understand, and have placed their faith in, the same promises of God that have sustained us. That's all that really counts in eternity.