Explain Philemon Chapter 1 verses 12-13?

Answer 1

Here Paul was in prison, he says that he is sending Onesimus , as he was not of much use then, but he has become better.

Additional information:

Onesimus was a run-away slave of Christian brother, Philemon, and not a very good person at the time he left. While on the run, however, he met Paul, heard and listened to the truth of God's word, applied what he learned in his life and became a Christian too. Because he now wanted to make things right, he was prepared to return to Philemon's household, so Paul was writing to Philemon, Christian to Christian, to explain what happened, that Onesimus (now a brother) should be forgiven based on Christian love, and saying that Paul would even pay for anything Onesimus owed Philemon.(John 13:35)

Because Onesimus was now a Christian, his ethics and behavior were better, and he had become a valuable person, especially to Paul, as he helped to take care of his needs while in prison, that's why he said that he'd like to hold him back.