Luke 23:11

‘And Herod with his soldiers set him at nought, and mocked him, and arraying him in gorgeous apparel sent him back to Pilate.'

Having exhausted his attempts to get something out of Jesus Herod was no doubt convinced that He was after all a fraud, and so proceeded to make fun of Him. He is the only one of all those who were ‘trying' Jesus who actually himself participated in this kind of treatment. The others had not interfered with it, but had not participated themselves (Matthew 26:67 probably has in mind the guards). It bring out Herod's unfitness to rule. But his behaviour might well have hidden a sense of awe of Jesus, similar to the sense of awe he had had of John the Baptiser. This was probably his way of indicating that Jesus had no power over him, especially to Pilate, while at the same time confirming His innocence.

So he and his soldiers made a mockery of Jesus and humiliated Him, and then mockingly arraying His bleeding figure in royal robes as though He were a king, sent Him back to Pilate. But this act was significant. It was Herod's callous way of indicating what his view was. Pilate could accept that his view was that the accusers were wrong and that in some kind of way, not to be taken too seriously, Jesus was a Messiah of sorts, but nothing to make a fuss about.