Luke 23:12
"And the same day Pilate and Herod were made friends together: for before they were at enmity between themselves."
Cross References (ranked by relevance)
Acts 4:27
For of a truth against thy holy child Jesus, whom thou hast anointed, both Herod, and Pontius Pilate, with the Gentiles, and the people of Israel, were gathered together,
Matthew 16:1
The Pharisees also with the Sadducees came, and tempting desired him that he would shew them a sign from heaven.