Also: Look in the mirror.
Meaning: Examine yourself.
James 1:23-24
For if any be a hearer of the word, and not a doer, he is like unto a man beholding his natural face in a glass: [24] For he beholdeth himself, and goeth his way, and straightway forgetteth what manner of man he was.
1 Cor. 11:28
But let a man examine himself, and so let him eat of that bread, and drink of that cup.
2 Cor. 13:5
Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates?