In his letter to the Corinthian church Paul makes the following statement about God’s faithfulness to the Corinthian believers:
He will also keep you firm to the end, so that you will be blameless on the day of our Lord Jesus Christ (I Corinthians 1:8 NIV).
This statement seems almost incredible in light of the rest of the letter. Throughout the rest of the book the Apostle Paul criticizes this church for being factitious (1:10-17), endorsing immorality (I Corinthians 5:1), and being unable to keep the peace amongst themselves (I Corinthians 6:6-7). And yet Paul expresses confidence that these believers will be counted “blameless” on the day of Christ’s appearing!
I do not think that Paul is saying here, that he expects the Corinthian believers to be perfect. It is true that he expects them to grow in grace, love, and righteousness, but he is not deluded about the struggles that they still face. He knows that they will keep struggling with the fleshly desires up until the day of their death. But they will still be counted “blameless” on “the day of our Lord Jesus Christ,” because their sins have been covered by Jesus’ blood. Some theologians disagree with me, but I believe that the “day” referred to here is Christ’s judgment on unbelievers. Jesus came to save the first time, the second time He comes back He will also fill the role of Judge (II Thessalonians 1:6-9). All those who have not repented and believed in Him will be punished eternally, but those who have believed will be blameless and will not be touched by this judgment.
However, that is not to say that there will be no consequences for true believers who still continue in some of their sins. They will be interrogated by God about everything they ever did in their life (Romans 14:10-12, II Corinthians 5:9-10). They will not be punished for their sins by being cast into hell, but they will lose many a valuable reward:
For no one can lay any foundation other than the one already laid, which is Jesus Christ. 12 If anyone builds on this foundation using gold, silver, costly stones, wood, hay or straw, 13 their work will be shown for what it is, because the Day will bring it to light. It will be revealed with fire, and the fire will test the quality of each person’s work. 14 If what has been built survives, the builder will receive a reward. 15 If it is burned up, the builder will suffer loss but yet will be saved—even though only as one escaping through the flames. (I Corinthians 3:1-15 emphasis mine).