In Genesis Abraham and Sarah are blessed by God. He tells them they will have a son, and his offspring will become a great and powerful nation. Both Abraham and Sarah find this hard to believe because they are so old, but God keeps his promise and Isaac is born. Because of this, Isaac is both unique and un-unique at the same time.
Isaac is unique because he was ordained by God. He wouldn't exist if God hadn't caused him to be brought forth. God had a special hand in his birth. Paradoxical this also makes him un-unique because we are all ordained by God. We all exist by God's will. In Psalm 139, David says, "(You) knit me together in my mother's womb". In Isaac, you could say all of humanity is being represented as he is being led up the mountain to be sacrificed.
The question Abraham and Isaac's journey asks is, why would God do this? Isaac is innocent, or at least as innocent as a human tainted by original sin can be. Regardless, one day, whether he is sacrificed or not, he will die. If God is a just and righteous God as we believe him to be, why would he bring this child into existence just for him to eventually die? This is the cruel reality for every human being on earth. From a nihilistic perspective, it would have been better if Isaac had never been born at all. One day he will die, his children will die, everyone on earth will die, and nothing will have mattered. It isn't hard to see how people can disregard sin and choose to live however they want under those circumstances. However, Abraham had a different answer. His answer was to have faith.
He does what God commanded him to do. Isaac is placed on the altar, and Abraham prepares to sacrifice him. This is the brutal climax of the story. Just before the deed is done, God stops him. He blesses Abraham for being willing to do his will. Abraham then looks up and finds a ram caught in a thicket. God provided him with a substitute, just as Abraham had prophesized to Isaac earlier.
God would take this template of events and bring salvation to all people 2000 years later. Jesus would ride a donkey up to the temple. The mountain the temple was on is believed by many to be the same one where Abraham was told to sacrifice Isaac. Later that night, the temple priests would have him arrested. He would be tried and turned over to Pilate who would then crucify him. The son of God, who is God and man, would be a sacrifice for all the sins of mankind.
Jesus ascent up the mountain seems almost symbolic. He is humanity rising up once more, reuniting with God. It wasn't something we could do by ourselves. God had to provide, just as Abraham said he would. Jesus's life and death were a substitute for ours. We receive it through faith, just as Abraham did.


