The OT saints believed the Word of God.
Abram was Called Out by the LORD unto salvation in His Living Word
Gen 15:6 - And Abram believed in the Lord, and He accounted it to him for Righteousness.
This Righteousness that was imputed to Abraham DIRECTLY from the LORD thru Faith in the Word = is Salvation
What then shall we say that Abraham our father has found according to the flesh?
For if Abraham was justified by works, he has something to boast about, but not before God.
For what does the Scripture say?
Abraham believed God, and it was accounted to him for righteousness.”
Now to him who works, the wages are not counted as grace but as debt. - Romans 4:3
And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, “In you all the nations shall be blessed.” So then those who are of faith are blessed with believing Abraham.
Jesus answered and said to them, “Are you not therefore mistaken, because you do not know the Scriptures nor the power of God? For when they rise from the dead, they neither marry nor are given in marriage, but are like angels in heaven.
But concerning the dead, that they rise, have you not read in the book of Moses, in the burning bush passage, how God spoke to him, saying, ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’?
He is not the God of the dead, but the God of the living. You are therefore greatly mistaken.” - Mark 12:24-27
SHALOM to ALL Living Saints in CHRIST JESUS our LORD