Listening to a sermon, I heard the word “restraining”, in the context of Jesus restraining Himself when he was spat on, et cetera.
A definition of restraining; "Preventing giving oneself to a strong urge" implying that there is evidence of a desire to lash back. We have all experienced this, and in my own personal experience it was having a large rock thrown at me while driving in Jerusalem, which gave rise to anger that I didn't know I had.
However, I would put it to you that Jesus was not in the frame of mind or heart to direct any anger at his executioners because he was denying and dying to his self-will throughout his life in his earthly ministry. He told his disciples he was the resurrection and the life, before he encountered the cross. The prerequisite for resurrection is death, and he denied his human capacity to anger even from the time his brothers would mock him for who he was, up till the time of Gethsemane and the hours thereafter. He denied his human self-will, so that when they spat on him he had no anger towards them, because of the Grace he lived by, which he has called us to live by. Contrary to reacting to his persecutors, he cried out to his Father, "forgive them, for they do not know what they are doing". There is no forgiveness when there is anger to be restrained. Unlike sin ladened humanity, he was devoid of anything that needed restraining! We have evidence of this in Philippians 2:8. Humility yields perfectly. Grace follows. And Jesus was full of Grace and Truth. He is our forerunner, and we are to follow him as he walked.
The greatest substitutionary element in the timeline of the cross, was not physical, the nails, the lashings, the crown of thorns, but separation from his Father which he offered up as substitute for our eternal separation from the Father. Anticipating the break in fellowship gave him such stress that he sweat great drops of blood onto the ground among the dense bed of spring flowers in the Garden of Gethsemane. Here, the God-man as divine and infinite spent a finite number of hours separated from his Father, eternity, so that I didn't have to, nor anyone else living by his faith. To equate that, a finite person would have to spend an infinite length of time, eternity, in the worst condition imaginable; separation from God. Even the ardent atheist enjoys, unwittingly, God's blessings. If God removed himself from any human being, that condition is simply hell.
Garden of Gethsemane, Jerusalem -circa 33 AD