What was the first physical abuse by the Romans that Jesus suffered?

Before He was taken to Pilate, Jesus had already been mistreated during His arrest and Jewish religious hearings. While He was before the high priest, one of the officers struck Him with the palm of his hand (John 18:22). Later, those holding Jesus mocked Him, spit in His face, struck Him with their fists, blindfolded Him, and beat Him while demanding that He prophesy who had struck Him (Matthew 26:67–68; Luke 22:63–65).

So by the time Jesus was delivered to the Roman authorities, He had already endured considerable physical abuse and humiliation.

As for the first physical abuse specifically inflicted by the Romans, it appears to have been the scourging ordered by Pontius Pilate (John 19:1; Matthew 27:26). Roman scourging was an extremely severe punishment in which the prisoner was repeatedly whipped.

Afterward, the Roman soldiers continued abusing Him. They placed a crown of thorns on His head, put a purple or scarlet robe on Him, mocked Him as “King of the Jews,” struck Him, spit upon Him, and beat Him on the head with a reed (Matthew 27:27–30; John 19:2–3).

So the sequence is important: Jesus’ physical abuse began under those involved in His Jewish trial, and the Romans later intensified that suffering through scourging, mockery, beating, and finally crucifixion.