that you will not do anything wrong: They would do wrong by following the false teachers who had appeared (11:5, 13–15; see study note on 10:1–13:13).
even if we appear to have failed: Paul’s goal in ministry is to be faithful, not to seem successful (1 Corinthians 4:2). He modeled his service on Jesus Christ himself (2 Corinthians 13:4), who seemed weak and a failure by dying on the cross. But Jesus is now victorious as he lives by God's mighty power.