What does John 12:47 mean?

Taken out of context, this verse can be misunderstood to mean that Jesus will never judge sin, or that all people will be saved, regardless of whether or not they believe in Him. However, in the prior verses, Jesus specifically said that those who did not believe in Him were "in darkness" (John 12:44–46). This corresponds to other statements Jesus has made about His role in our salvation (John 8:12). As part of those teachings, Jesus has made it clear that those who do not accept Him by faith cannot be saved (John 3:36). Later, when speaking to the disciples, He will explicitly state that no one can come to God except through Christ (John 14:6). This proclamation highlights the fact that the words and deeds of Christ are the very words and will of God the Father (Hebrews 1:3; Colossians 1:15).

The birth, life, and death of Jesus Christ as a man was His "first coming" to earth. The comment made here by Jesus is a reminder that His role in this first coming is not the final or literal judgment of sin. His purpose is to establish the means by which mankind can be saved (John 12:27–32). The book of Hebrews reminds us that when Jesus returns, His role will be exactly the opposite (Hebrews 9:27–28). In that second coming, Jesus will arrive to administer judgment, not to offer forgiveness (Revelation 19:11–21).

The following verse reiterates this idea: there is in fact a judge who will separate those who have believed in Christ from those who have not (John 3:16–18).