Made friends together - What had been the cause of their quarrel is unknown. It is commonly supposed that it was Pilate's slaying the Galileans in Jerusalem, as related in Luke 13:1-2. The occasion of their reconciliation seems to have been the civility and respect which Pilate showed to Herod in this case. It was not because they were united in "hating" Jesus, as is often the case with wicked people, for Pilate was certainly desirous of releasing him, and "both" considered him merely as an object of ridicule and sport. It is true, however, that wicked people, at variance in other things, are often united in opposing and ridiculing Christ and his followers; and that enmities of long standing are sometimes made up, and the most opposite characters brought together, simply to oppose religion. Compare Psalm 83:5-7.

Pilate and Herod were made friends - I do not find any account of the cause of the enmity which subsisted between Herod and Pilate given by ancient authors; and the conjectures of the moderns on the subject should be considered as mere guesses. It is generally supposed that this enmity arose from what is related Luke 13, of the Galileans, whose blood Pilate hath mingled with that of their sacrifices. These were Herod's subjects, and Pilate seems to have fallen on them at the time they were offering sacrifices to God at the temple. Wicked men cannot love one another: this belongs to the disciples of Christ. But when Christ, his truth, or his followers are to be persecuted, for this purpose the wicked unite their counsels and their influence. The Moabites and Ammonites, who were enemies among themselves, united against poor Israel, and, as Rabbi Tanchum says, may be likened to two contending dogs, who, when the wolf comes, join together to destroy him; each knowing that, if he do not, the wolf will kill both in succession: whereas, by their union, they may now kill or baffle him. There is a proverb among the rabbins, that, when the cat and weasel marry together, misery becomes increased.

(3) And the same day Pilate and Herod were made friends together: for before they were at enmity between themselves.
(3) The hatred of godliness binds the wicked together.

And the same day Pilate and Herod were made friends together,.... For it pleased Herod, that Pilate should show such a regard to his authority and power, as to send one that belonged to his jurisdiction to take cognizance of his case; and especially as it was a person that was much talked of, and he had long wanted to see; and Pilate, on the other hand, was pleased with Herod, that though he was one that was under his jurisdiction, and so had a right of trying the cause, and either absolve or condemn, yet chose not to use this his power, but referred the case to the Roman governor:
for before they were at enmity between themselves; it may be on account of the Galilaeans, the subjects of Herod, whom Pilate had slain, whilst they were sacrificing at Jerusalem, Luke 13:1, which Herod might resent, as an infringement upon his authority and power; for had they been ever so deserving of punishment, it ought to have been left to him, to have inflicted it, and not the governor of Judea, who had nothing to do with them: but now matters were made up by this step of Pilate's, in sending Christ to him, supposed to be a Galilean, and so of Herod's jurisdiction; which was tacitly acknowledging his former conduct to be wrong, and showed a regard to Herod's authority: and thus they were reconciled together, and agreed in their contemptuous usage, and ill-treatment of Christ, and so fulfilled Psalm 2:1.