# my child Onesimus

"my spiritual son Onesimus"

# Onesimus

The name "Onesimus" means "profitable" or "useful". He was apparently Philemon's slave and had stolen something and run away.

# whom I have fathered in my chains

"who became my spiritual son when I taught him about Christ and he received new life while I was in my chains" or "who became like a son to me while I was in my chains"

# in my chains

"while I have been in prison" or "while I was in prison"