It wasn’t merely a test, but a foreshadowing of the coming of the Son of God. To wit, Then God said, “Take your son, your only son, whom you love—Isaac—and go to the region of Moriah. Sacrifice him there as a burnt offering on a mountain I will show you.”
The same thing is true regarding all sacrifices; that’s why God implemented it. In an extrabiblical account, an angel confronts Adam: “And then the angel spake, saying: ‘This thing is a similitude of the sacrifice of the Only Begotten of the Father, which is full of grace and truth. Wherefore, thou shalt do all that thou doest in the name of the Son, and thou shalt repent and call upon God in the name of the Son forevermore.’”
Animal sacrifices were introduced by God as a teaching implement: to teach His people about the ultimate sacrifice by the Savior, Jesus Christ. We see this throughout the scriptures. Note, for example, the prophet Zechariah speaking of the battle of Armageddon:
And it shall come to pass in that day, that I will seek to destroy all the nations that come against Jerusalem. And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn. In that day shall there be a great mourning in Jerusalem, as the mourning of Hadadrimmon in the valley of Megiddon.
In the day of their salvation, when the Beast Daniel and John spoke of, Jesus will appear to the Jews. To them, it’s the coming they had been waiting for for generations. In the midst of their tribulation, the Messiah appears in great glory (which is how the Jews have always expected the Messiah to come). They had hoped it would happen in the days of the Romans, but according to scripture, they were dispersed to the four corners of the earth. In the last days, however, they gather to the lands of their inheritance. And when their enemy is about to destroy them, they are delivered. Note the reference to the fact that the Messiah will be “pierced.” And the Jews will ask, “What are these wounds in thy hands,” and the Messiah will say, “These are the wounds I received in the house of my friends.” (See Zechariah 13) Then the Jews will realize who their Messiah is and the entire land will go into a state of mourning.
Not only does Zechariah say the Jews will mourn for their Messiah “as one mourneth for his only son,” he says they will be in bitterness “as one that is in bitterness for his firstborn.” So you have two prophetic references in relation to the Messiah: 1) the only begotten Son of God and 2) the firstborn Son of God. This was written hundreds of years before Jesus, and yet in the prophecy we see a teaching that relates to Jesus.
God knows the choices we’ll make in life, but unless we actually make those choices, we don’t grow. He also knows what each of us will do in our lives and whether we will receive eternal life or lesser glories. People say, “Well, if He knows how it will turn out, why does He make us go through it?” It’s for the same reason a Navy Seal recruit knows he’ll make the grade, but he has to do it. Our experiences on Earth determines how and where we spend eternity, but we have to go through them for our own growth.
BTW, there are a number of extrabiblical accounts indicating that Abraham suspected that God would either stop him or, if he sacrificed his son, God would raise him up. The scriptures indicate he was a “friend” of God, and I suspect Abraham knew God well enough to know that Isaac would be delivered.
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