"What does this reveal about God and His salvation?"
That's the question the Israelites, the original readers, asked when they read their Bibles. When they asked Genesis 22 this question, they got four answers.
God demands sacrifice
Israelites reading Genesis 22 had the huge advantage of knowing the rest of Genesis. They knew sacrifice was instituted by God, required by God, and frequently offered to God by Old Testament believers such as Abel, Noah, Abraham, Isaac, and Jacob.
They also had the advantage of having experienced the Passover and the Levitical system of sacrifices formally organized at Sinai.
With this background, the Israelites would not be surprised when they read in Genesis 22 that God demanded a sacrifice from Abraham. That was par for the course; it was normal, everyday life for them.
"Of course God demanded sacrifice. He is holy, He is offended by sin, and He demands sacrifice to cover sin, appease His anger, and restore fellowship with sinners."
What was surprising in Genesis 22, indeed stunning, was the nature of the sacrifice – Isaac!
God dictates the sacrifice
Isaac! Sacrifice Isaac! Abraham, offer your son, your only son, the son you love, as a burnt offering.
From Cain and Abel onwards, Israel was used to the idea of God determining what sacrifice would be acceptable and what would not. It wasn't up to sinners to decide. As the offended party, God alone could dictate the terms.
If He said, "A one-year-old lamb," nothing else would do. If he said "Isaac!" Isaac it had to be, as Abraham's remarkable obedience makes clear. There's no gap or discussion between the command and, "He rose up early the next morning…and took Isaac his son."
Both Abraham and Isaac comply. They know that the wages of sin is death and if God says, "Isaac must die," then who were they to argue? God dictates the sacrifice.
God substitutes the sacrifice
The idea of substitution, an animal life in exchange for human life, was present from the first sin onwards in Genesis 3. But never had a human life come so close to actually becoming a sacrifice.
The Israelites had watched animal sacrifices. They had even participated in sacrificial rituals like the Passover, where they laid their hand on the lamb's head to transfer their guilt, slit the lamb's throat, collected it's blood, and burned the carcass.
But they had never been personally bound on an altar of wood; they had never had a knife raised above their heads. That's what makes this narrative so unique, so revealing, so powerful, so shocking.
God stops the killing of Isaac at the last moment.
Abraham hears a bleating and turns round to find a ram caught in a bush.
No further instructions are necessary. Isaac and the ram exchange places, the knife is raised again, and this time it plunges deep into the ram, the fire is lit, and the flames leap heavenwards.
Imagine those spiritually intense and intimate moments as Abraham and Isaac watched the flames, smelt the smoke, felt the heat.
"That could have been you, son."
"That should have been me, Dad."
God provided a substitute sacrifice.
God is satisfied by sacrifice
In what way did animal sacrifices satisfy God? It's common to think that they actually atoned for moral guilt and secured eternal life for the offerer.
However, the New Testament makes clear what Old Testament consciences often felt: "The blood of bulls and goats could never take away sin," – not from the sinner's conscience and not from God's records.
These sacrifices did however offer a more limited and temporary atonement and forgiveness. They purified the flesh, they re-admitted sinners (both individuals and the nation) to physical proximity to God, and they allowed sinners to take their place in the camp, in the ceremonies, etc.
No spiritually minded Israelite ever imagined that an animal sacrifice could form the basis of his salvation. Rather, it made him long in faith for a better and greater sacrifice that would fully and forever cover his sin, satisfy God, and pacify his own conscience.
God becomes the sacrifice
Neither Abraham, Isaac, nor any Israelites at that time could have ever fully grasped that God would one day not only demand sacrifice, dictate the sacrifice, substitute the sacrifice, and be satisfied with sacrifice, but would also actually become the sacrifice.
The Son of God understood it, as He watched from heaven and anticipated that awesome day. He also increasingly understood it as He grew in knowledge of His Bible, especially of Genesis 22, during His time on this earth.
And when it came for Him to not just understand but experience Genesis 22, He willingly stretched out His life on the altar as a sacrifice to cover human sin completely and satisfy divine justice totally. And when the knife was raised and the fire set, there was no "Baa!"
There was no substitute for Him, so that there would be one for us.