What does Revelation 3:3 mean?
In this verse we find a challenge from Jesus and a warning about what will happen if the church at Sardis rejects the challenge. Jesus challenged the church to remember, recapture, and repent. It needed to recall the truth it had received when it first received it. The Lord had given the truth to the church as a permanent deposit that it was supposed to guard zealously.Any church that is sliding away from the truth must remember its initial encounter with Christ. Jesus challenged the church at Sardis to repent—to change its mind. Instead of continuing its slumber, thinking its current condition was all right, it was to wake up. The original city of Sardis felt complacent, thinking no attack against it could prevail, but it was wrong. It had relaxed its sentry duty and experienced a sudden downfall, decades prior to this letter.
Similarly, the church at Sardis would fall if it failed to be watchful. The church cannot assume it has already "done enough" for God. If the church at Sardis did not wake up, Jesus would come like an unexpected and unwelcome thief. Christians who slumber in complacency do not live up to their high calling in Christ Jesus. When Jesus comes unexpectantly, those slumbering believers will forfeit their rewards at His Judgment Seat (1 Corinthians 3:13–15; 2 Corinthians 5:10).