'Unworthy' in the Bible

"Indeed, I am completely unworthy -- how could I reply to you? I put my hand over my mouth to silence myself.

For this reason, whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord.

For I am the least of the apostles, unworthy to be called an apostle, because I persecuted the church of God.