Clearly, Old Testament saints were aware of the promised Redeemer, and they were saved by faith in that Savior, the same way people are saved today. The difference is that they looked forward to a promise, and we look back to an event.
There is no other way. Jesus is “‘the stone you builders rejected, which has become the capstone. "Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved.”
There is a movement among the big name big church boys who have made themselves smarter than God by teaching the cross was not important. They proclaim that God would never demand a human blood sacrifice. They proclaim that we are saved from the perfect life and example of Jesus and not by His sacrificial blood atonement. The official named of this false doctrine is "Moral Government Theology."
These smart TV preachers speak a lot that sounds good to itching ears but you will never here them preach on the cross. Much learning has made them foolish in their doctrines of demons. Yet unaware believers are drawn to them by their great music program and their high lofty words. I say what the WORD of God says. There is no remission of sins without the shedding of blood.
Acts 4:11-12 ESV This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone. (12) And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.”
Psalms 118:22 ESV The stone that the builders rejected has become the cornerstone.
What failed us for the removal of sin? The Old Testament sacrificial system did not take away sin, as Heb.10:1-10 clearly teaches. It did, however, point to the day when the Son of God would shed His blood for the sinful human race.
Hebrews 10:1-10 ESV For since the law has but a shadow of the good things to come instead of the true form of these realities, it can never, by the same sacrifices that are continually offered every year, make perfect those who draw near. (2) Otherwise, would they not have ceased to be offered, since the worshipers, having once been cleansed, would no longer have any consciousness of sins? (3) But in these sacrifices there is a reminder of sins every year. (4) For it is impossible for the blood of bulls and goats to take away sins.
(5) Consequently, when Christ came into the world, he said, “Sacrifices and offerings you have not desired, but a body have you prepared for me; (6) in burnt offerings and sin offerings you have taken no pleasure. (7) Then I said, ‘Behold, I have come to do your will, O God, as it is written of me in the scroll of the book.’” (8) When he said above, “You have neither desired nor taken pleasure in sacrifices and offerings and burnt offerings and sin offerings” (these are offered according to the law), (9) then he added, “Behold, I have come to do your will.” He does away with the first in order to establish the second. (10) And by that will we have been sanctified through the offering of the body of Jesus Christ once for all.