Hebrews 9:27 states that "it is appointed for all men to die once, but after this the judgment." And the apostle Paul told Christians, "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" (2 Corinthians 5:10; compare Romans 14:10). Yet the apostle Peter wrote, "For the time has come for judgment to begin at the house of God; and if it begins with us first, what will be the end of those who do not obey the gospel of God?" (1 Peter 4:17-18). The house of God is God's Church (1 Timothy 3:15), comprising all true Christians. Thus, a converted Christian's time of judgment is now—in this life—though ultimate judgment will be declared in the future at the resurrection.
As Peter says, we are judged according to how we "obey the gospel of God." This includes obeying God's commandments (see Matthew 19:17; 1 Corinthians 7:19; Revelation 22:14). Too many who profess to be Christians or religious do not practice in their daily lives what the Bible teaches. For example, in a recent Barna survey only about one fourth of those who consider themselves servants of Jesus Christ placed faith as their highest priority in life. Barna concluded that there is a significant disconnect between what religious people say and what they do. That must not be so among true followers of Christ.
As Paul wrote, over time one's work will become clear (1 Corinthians 3:13)—the fiery trials and tests we experience in this physical life revealing the character we have developed (Romans 5:3-4). Everyone's personal spiritual house is going to be tested and tried by fire right down to the depths of its foundations. So we must take heed how we build our spiritual house. Again, God is judging His Church now.
Yet we must realize that this judgment is an evaluation over the course of our Christian lives and not an immediate sentencing. And Jesus, to whom all judgment has been committed because He lived as a human being, is sympathetic to our condition and intercedes for us with the Father as our High Priest (John 5:22, John 5:26-27; Hebrews 2:17-18; Hebrews 4:15). He knows that we will not achieve instant perfection in the flesh but must mature and grow throughout our years to become more and more like Him.
While human, we will still sin at times even after conversion, but God is merciful, always willing to forgive us upon repentance and faith in Christ to save us. As the apostle John wrote: "If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. If we say that we have not sinned, we make Him a liar, and His word is not in us. My little children, these things I write to you, so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous. And He Himself is the propitiation [or atonement] for our sins, and not for ours only but also for the whole world" (1 John 1:8-10 - 1 John 2:1-2, emphasis added).
Yet for converted Christians there is no longer atonement if we stop repenting—that is, stop striving to obey God (Hebrews 2:1-3; Hebrews 6:4-7; Hebrews 10:26-31, Hebrews 10:35-38). So we must continue in the process of conversion with God to make our "call and election sure" (2 Peter 1:10). And we can have confidence in God to see us through (Philippians 1:6; Hebrews 13:5).
Then at the end we can hear words like these from Christ: "Well done, good and faithful servant; you were faithful over a few things, I will make you ruler over many things. Enter into the joy of your lord" (Matthew 25:21). Our individual rewards in God's Kingdom at the resurrection will also be determined through God's judgment of our works in this life (Matthew 16:27)—judgment that, again, is with mercy. God assures us in James 2:13, "Mercy triumphs over judgment."