ISB ~ 2 Timothy 1 v8

his prisoner:Paul is nearly alone (4:10-11) and chained up like a criminal (2:9), suggesting this does not refer to his first Roman imprisonment, where he lived more comfortably under house arrest and was surrounded by friends and crowds eager to listen to him (Acts 28:16-31). Most likely, this refers to his second Roman imprisonment, which is attested by early traditions that supply details about the end of Paul’s life.

See introduction:Date.