Hebrews 13:3

The prisoners in view were evidently Christians who were suffering for their testimonies (cf. Hebrews 10:34; Matthew 25:36; Matthew 25:40). Often prisoners in the Roman world had to depend on friends outside the prison to provide them with food and other necessities. The existence of a significant number of prisoners supports a date for writing after A.D. 64, when an empire-wide persecution of Christians began. In July of that year, Emperor Nero set fire to Rome and blamed the Christians, resulting in much persecution of Christians. The readers might suffer the same fate as these prisoners themselves one day since they were still leading a mortal existence. Paul urged Timothy not to be ashamed of him when he was a prisoner (2 Timothy 1:8). All the Christians in the province of Asia had abandoned Paul then except for those in Onesiphorus’ household (2 Timothy 1:15-18).