In your struggle against sin, you have not yet resisted to the point of shedding your blood. (Hebrew 12:4)

The Greek word translated ‘struggle’ is ἀνταγωνίζομαι  antagónizomai, from anti ‘against’ and agónizomai ‘contend with’, whence English derives the verb ‘to agonise’.  The common usage of agónizomai was in the context of warfare or an athletic contest, and it refers to the physical, mental and emotional exertion in contending with an enemy.

The writer of Hebrews references Jesus in the garden of Gethsemane, who –

knelt down and prayed, saying, “Father, if you are willing, remove this cup from me. Nevertheless, not my will, but yours, be done.” And there appeared to him an angel from heaven, strengthening him. And being in an agony he prayed more earnestly; and his sweat became like great drops of blood falling down to the ground.And when he rose from prayer, he came to the disciples and found them sleeping for sorrow, and he said to them, “Why are you sleeping? Rise and pray that you may not enter into temptation.”  (Luke 22:42-46)