What does Romans 14:12 mean?

Paul sums up the message of his previous two verses in one simple sentence. Each one of us will give an account of ourselves to God at some future moment in the end times. Paul included himself here. He, too, will give an account of himself to God. Critically, Paul's point here is that this account is not given to other Christians (Colossians 2:16–23). This passage speaks of the need to tolerate fellow believers when they have a different opinion on a non-essential issue. A heavy motivator for that tolerance is the fact that we, ourselves, are not that other Christian's ultimate master; God is.

Paul is talking about what is known as the judgment seat of Christ, described more fully in 2 Corinthians 5:10. This judgment will not be about salvation. God will not respond to the account we give of ourselves here and then decide if we deserve heaven or hell. If He did, each of us would be sent to hell. Paul wrote in Romans 3:23 that all of us have sinned and fallen short of God's glory. Rather, the decision about whether we will be allowed into heaven or not has already been made for those of who are in Christ. It was finished the moment we came to Him in faith (Ephesians 2:8–9).

Instead, we will give to Christ an account of our works in this life and they will be shown to be lasting or worthless. Christians will be rewarded for their lasting works and suffer loss of some kind for their worthless ones. Everyone there, though, will stand in Christ and be saved (1 Corinthians 3:12–15).