My pleasure, salvation has always been by grace thru faith. This was true under law and remains true under grace. Grace is always from God but faith comes from us.
During the dispensation of the law, you exhibit faith by "obeying the law", all the Jews have to obey the law. It is true that all the saints of past ages were saved through the merits of Christ's shed blood, but not through their faith in that shed blood.
Those of past ages were expected to believe only what God had thus far revealed, or what He had revealed to them. In other words, they were saved simply because they trusted God and believed what He said. The full plan of salvation has since been unfolded, but the Scriptures make it crystal clear that these believers were saved without even understanding that Christ would die for them.
When God says, "Sacrifice an animal every time you sin," what will faith do? Just one thing: sacrifice an animal whenever you sin. We know, thanks to Hebrews, that such sacrifices are a mere shadow of the coming Jesus as the final Lamb, yet not one of their hearers would have interpreted this action to mean what it meant in Paul's Gospel: "Trust in the death of Christ for salvation."
But once the age of grace began, this is now what is required to show faith.
"BUT NOW the righteousness of God without the law is manifested" (Rom. 3:21);
"To him that worketh not, but believeth on Him that justifieth the ungodly, his faith is counted for righteousness" (Rom. 4:5)
"Being Justified freely by His grace, through the redemption that is in Christ Jesus" (Rom. 3:24);
"In whom we have redemption through His blood, the forgiveness of sins according to the riches of His grace" (Eph. 1:7);
"Not by works of righteousness which we have done, but according to His mercy He saved us" (Tit. 3:5);
"Not of yourselves: it is the gift of God: not of works, lest any man should boast" (Eph. 2:8,9)
When God now says this, what will faith do? Faith will say, "This is the most wonderful offer ever made by God to man. I cannot refuse it. I will trust Christ as my Savior and accept salvation as the free gift of God's grace."
Trust me when I tell you, everyone else from the Old Testament, King David, Noah, even the 4 Gospels guys such as Peter, James and John, will be very envious about you.
Their conditions for showing faith were not as simple as what we have to do, under the age of Grace.
- Noah had to build an ark. (Hebrews 11:7)
- Abel had to bring the correct sacrifice (Gen 4:4-5, Heb. 11:4)
- Abraham had to believe, at his advanced years, that God would make him a father of many (Genesis 15:5-6)
- Rahab had to hide the spies, at the risk of being caught and punished (Hebrews 11:31)
The point is that, by the time it reach us Gentiles, thanks to Jesus ushering the age of Grace, all we need to do, in order to display faith, is simply believing and speaking.