John Calvin on John 18:3

3. Judas, therefore, having received a band of soldiers. That Judas came accompanied by soldiers and by so large a retinue, is a sign of a bad conscience, which always trembles without any cause. It is certain that the band of soldiers was borrowed from the governor, who also sent a captain at the head of a thousand soldiers; for, on account of sudden mutinies, a garrison was stationed in the city, and the governor himself kept a body-guard, wherever he was. The rest were officers sent by the priests; but John makes separate mention of the Pharisee, because they were more enraged than all the rest, as if they had cared more about religion.