David begins with his plea for God to forgive him, appealing to His
Loving kindness and tender mercy. Note that he does not ask God to
Forgive him based upon any good he may have done in the past.

Ezekiel continues to proclaim that judgment is, imminent, but the people will not believe.

Paul sent the runaway slave Onesimus back to Philemon from Rome with a letter to Philemon.  Paul makes his appeal to Philemon to forgive Onesimus on the basis of Paul’s love for Onesimus and Philemon’s love for Paul. Paul does not pull rank but makes an appeal based on his status as a troubadour for the cause of Christ.

Thirteen books in the New Testament begin with the name “Paul”. None of his books begin with “a prisoner of Christ Jesus” except this one. Philemon is the only epistle where Paul portrays himself as a “prisoner.” He currently sits in prison in the city of Rome. Paul refers to his imprisonment six times. Philemon is the fourth prison epistle.
(Philemon:1)