Now, we have no record of his early life except for his circumcision at age 8 days, and also probably around age 2 he was weaned and he was mocked by Ishmael. Now the supreme moment in his life undoubtedly occurred early in his young manhood.
The word translated, “lad” both here and in verse 5, means an unmarried child still in his father’s house. Josephus says that Isaac was 21. Other commentaries that I have read speculated anything from age 12 or 13 up to about 25. Some in the church speculated that he might have been thirty-three and a half. That if he was the type of Christ as a fulfillment of the promise, is it unwise, is it unreasonable to speculate that he carried it right on through in that Isaac was thirty-three and a half years when Abraham went to sacrifice him. Nobody knows, and in the long run it is unimportant.
What is important is Isaac’s willing submission to his father even to the point of death. If indeed Isaac was a young man in the full bloom of his life, full bloom of his strength, and his hopeful anticipation of his future of getting married and having children, then what he did here is extremely impressive. If Isaac was indeed 21, or 25, or 33, surely he would have been able to overpower or get out of the grasp of his 120+ year old father and run away. But he did not do that.
So, you see Isaac as a young child and on up through his teen years as a young man, had been taught by his father about the great God and His purpose and promise and the part Isaac was to play in that. I believe that Isaac too had a pretty great measure of faith. It was not just in his father, but that faith ascended through his father and on up to God.
What question must God have answered concerning of us?
He said, "Now I know you will obey Me! Now I know that you fear Me, and now I know you!"
Was this trial, and its positive conclusion, just for Abraham, the father of the faithful, or is it absolutely for every one of us as well? God the Father and Jesus Christ have to have that question answered as it concerns me individually, and they have to have it answered as it concerns you individually.
The statement God made to Abraham, He has to make of everyone who will be in His Kingdom. God has to say of each one of us, whatever our names are: Now I know you fear Me; "Now I know you!" We are not accepted because we belong to this or that group, we are accepted based on our individual performance in this calling given to us.
In verses six through twelve Isaac's faith in God is shown in his submission to his father and it comes to the fore. But at this point it is not the main point of the story. But it too is a major example as well.