Salvation has always and always will be by grace through faith. The issue of faith is faith in what. Old Testament Saints faith was different than the faith of those on this side of the death, burial, and resurrection of the Messiah. There are seven judgments which take place during the different dispensations.
The Believer's Sins
1. Believers sin were judged by the sacrifice of the Messiah:
2 Corinthians 5:21 He made Him who knew no sin to be sin on our behalf, that we might become the righteousness of God in Him.
The Believer's Self Judgment
2. Believers should judge themselves and not others.
1 Corinthians 11:31-32 For if we would judge ourselves, we would not be judged. But when we are judged, we are chastened by the Lord, that we may not be condemned with the world.
The Believer's Works
3. Believers works, not sins, will be judged for gain or loss of rewards.
2 Corinthians 5:10 For we must all appear before the judgment seat of Christ, that each one may receive the things done in the body, according to what he has done, whether good or bad.
The Gentile Nations
4. Living Gentiles will be judged at the Second Coming of the Messiah.
Matthew 25:32 "All the nations (ethnos ie Gentiles) will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats.
The Nation Israel
5. Israel as a nation will be judged during the Time of Jacob's Trouble:
Ezekiel 20:37-38 "I will make you pass under the rod, and I will bring you into the bond of the covenant; "I will purge the rebels from among you, and those who transgress against Me; I will bring them out of the country where they dwell, but they shall not enter the land of Israel. Then you will know that I am the LORD.
The Angelic Beings
6. Angels will be judged at the Second Coming Judgment:
Jude 1:6 And the angels who did not keep their proper domain, but left their own abode, He has reserved in everlasting chains under darkness for the judgment of the great day;
7. All Dead will be judged at the end of the Messianic Kingdom:
Revelation 20:12-15 And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books. The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works. Then Death and Hades were cast into the lake of fire. This is the second death. And anyone not found written in the Book of Life was cast into the lake of fire.
From Yehuatyisrael website