Hebrews 12:4

The readers had not yet resisted sin to the extent that their enemies were torturing or killing them for their faith, as had been Jesus’ experience. Evidently there had been no martyrs among the readers yet, though the writer and the readers undoubtedly knew of Christians elsewhere who had died for their faith (e.g., Stephen, James, et al.). Their striving against sin probably refers to both resisting sinful opponents and resisting temptations to sin in their own lives (Hebrews 12:1).