He's an infinite God making a sacrifice which made him infinitely merciful and infinitely just.
Was the sacrifice itself infinite?
John 8:56 Your father Abraham rejoiced to see my day: and he saw it, and was glad.
Luke 24:26-27 Ought not Christ to have suffered these things, and to enter into his glory? And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.
Apparently Abraham had a vision which is not recorded in the OT where he saw the future Jesus and what would come to pass. Moses and the rest understood there would be a great and last sacrifice made.
He was "the Lamb slain from the foundation of the world" so yes Abraham and others could be saved through their faith in a coming event as we are saved in something which is passed.
No it does not say or mean: “they were saved through a coming event”, their faith saved them in what they knew and the promises made. Jesus is talked about being the savior, but those prior to Christ coming in the flesh depended on their faith in deity.
Ro. 3:25 really explains this:
The Crucifixion is described by Christ, Paul, Peter, John (in Revelations) and the Hebrew writer as a literal ransom payment.
From Romans 3: 25 Paul tells us: God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith. …
Another way of saying this would be “God offers the ransom payment (Christ Crucified and the blood that flowed from Him) to those that have the faith to receive that ransom.
God is not the undeserving kidnapper nor is satan, but the unbeliever is himself holding back the child of God from the Father, that child that is within every one of us.
Paul goes on to explain:
(NIV) Ro. 3:25 God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith. He did this to demonstrate his righteousness, because in his forbearance he had left the sins committed beforehand unpunished—
“God presented” this might be better expressed as “God is offering” since it will later be received, received or rejected on the contingency of some kind of “faith”. Instead of received it might better be translated as accepted (with the option of being rejected or not accepted).
“Sacrifice of atonement” is described by Jesus, Paul, Peter, John and the Hebrew writer as the “ransom payment” or just “ransom”. So God is offering a ransom payment to be accepted by those with faith or rejected by those refusing or just not accepted by those lacking faith.
A huge part of that ransom payment that especially applies to those that are already Christians is the life giving cleansing blood of Christ. Christ and God would have personally preferred that blood remained in Christ’s veins, but I needed it given up by Christ to flow over both my outside and my heart to know, experience, “trust” and feel I am cleansed and made alive. So Christ willingly gave up His blood for me and because of me. This is an overwhelming tragedy I insisted on to believe: I was made holy, righteous and stand justified. Without knowing and feeling this blood flowing over my heart, I might question my cleansing?
“Demonstrate his righteousness” God did not become righteous, but just showed the righteousness He has always had. (God’s justice/ holiness/being right) comes with the atoning sacrifice that includes the life giving cleansing blood showing God’s righteousness/justice in a very particular way; by resolving the huge problem that existed under the Old Covenant. That huge problem in the Old Covenant was with the handling of intentional sins that where committed, repented of, and which the individual sought forgiveness from God for doing (and God forgave without justly disciplining the sinner [thus not showing His righteousness through His disciplining]). These sins could be forgiven by God, but there was no way to fairly/justly discipline (punish) the sinner and still have the sinner live in the Promised Land. God did have fair/just punishments (discipline) for these sins, but the Jews could not follow through with them, since all Jews deserved to be treated similarly (there would be no one left in the Promised Land).
“in his forbearance he had left the sins committed beforehand unpunished” Instead of “unpunished” I would translate that Greek word to be “undisciplined”.
“because in his forbearance he had left the sins committed beforehand unpunished”, shows the contrast between before and after the cross. This is not saying: “before the cross sins are now being punished by Christ going to the cross”, but is saying they were left unpunished prior to the cross. If they are being handled the “same way” as sins after the cross there would be no contrast? (And there are lots of other problems with this reasoning.) There is no “punishment” (disciplining for intentional sins) before the cross yet there is “punishment” (disciplining of God’s children) with the cross.
Any good parent realizes the need for not just forgiving their rebellious disobedient child, but to also see to the child’s fair/just/loving discipline if at all possible, but under the Old Covenant there was no “fair/just/loving discipline” so God could not show His justice/righteousness except to point out in the Law what really should happen, but that is not “good” disciplining, the child can almost feel they got away with something.