Hebrews 12:4

Resisted unto blood. That is, unto death. Here the metaphor of verses 1 and 2 changes slightly. The Christian is still in the arena with the figurative “cloud of witnesses” gazing intently at him, but now he is confronted by an antagonist waiting to engage him in mortal combat. The Christian has not yet experienced all that the evil one can bring against him, nor should he think that he is suffering more in his struggle with sin than God can rightfully expect of him (see 1 Corinthians 10:13). Nevertheless, in disentangling himself from his besetting sin he is called upon to resist temptation with all the resolute firmness that he would employ in meeting an antagonist in mortal combat.

Christ once engaged in such combat with the powers of darkness, a combat that reached its climax in Gethsemane and on the cross. The martyrs likewise “resisted unto blood.” But those to whom the book of Hebrews was written had not as yet been called upon to meet what Christ and the martyrs had met.