There is a source of confidence in the face of any self-doubt or challenge in life. Our text talks about those who are confident as they eagerly wait for the Return of Christ on the Last Day.
Our source of ultimate confidence is rooted in the person (who He is) and work (what He has done) of Jesus Christ.
We can confidently live our lives in eager expectation in Christ because once and for all, Christ has dealt with the root cause of our lack of confidence – sin.