Adam Clarke on John 18:6

They went backward, and fell to the ground - None of the other evangelists mentions this very important circumstance. Our Lord chose to give them this proof of his infinite power, that they might know that their power could not prevail against him if he chose to exert his might, seeing that the very breath of his mouth confounded, drove back, and struck them down to the earth. Thus by the blast of God they might have perished, and by the breath of his nostrils they might have been consumed: Job 4:9.