Jesus Christ was a marked man right from the minute of His birth. Herod The Great wanted to have Him killed as a newborn infant, and murdered many other male Jewish babies while trying to do so (Matthew 2:16-18). But Jesus survived that attempted assassination, and perhaps hundreds of others by Satan over the next more than 30 years, thanks to the angels who were given the responsibility of protecting Him - until the day came when they were given their orders to, in effect, just, "Stand back now, and let it happen."
Angels are very powerful spirit beings. Any one of them could have wiped out an entire Roman legion (e.g. 2 Kings 19:35), and yet that day they had to just stand and watch the horrendous brutality being inflicted on the Son of God by those evil Roman thugs whose "bravery" apparently only existed while together in their greater numbers - individually, most (there were exceptions) were cowards who feared facing an opponent in a fair fight. Roman legions typically lived and fought in massive formations, which although it was their greatest strength, when their opponents let them have the initiative, it was also their greatest weakness when they faced an opposing commander who bided time and circumstances to fight them one-on-one e.g. when a force of Germanic warriors under Hermann annihilated 3 full Roman legions after challenging the "invincible" Romans into the dense forests of Germany where the rigid Roman battle formations quickly broke down, forcing the Roman troops to fight, not as cogs in a killing-wheel, but as individuals.
Despite their being spirit beings, we know that angels can experience emotion (e.g. Job 38:7), so it's not too hard to imagine that they stood there in great dismay, perhaps with tears of, not just grief, but absolute fury streaming down their faces, knowing that they could so easily have stopped it, as they watched this:
Insulted, Spit Upon, Beaten While Tied and Blindfolded
"But Jesus was silent. And the high priest said to Him, "I adjure You by the living God, tell us if You are the Christ, the Son of God." Jesus said to him, "You have said so. But I tell you, hereafter you will see the Son of man seated at the right hand of Power, and coming on the clouds of heaven."
"Then the high priest tore his robes, and said, "He has uttered blasphemy. Why do we still need witnesses? You have now heard His blasphemy. What is your judgment?" They answered, "He deserves death."
"Then they spat in His face, and struck Him; and some slapped Him, saying, "Prophesy to us, You Christ! Who is it that struck You?" (Matthew 26:63-68 RSV)
Mocked, Abused and Crucified
"Then the soldiers of the governor took Jesus into the praetorium, and they gathered the whole battalion before Him. And they stripped Him and put a scarlet robe upon Him, and plaiting a crown of thorns they put it on His head, and put a reed in His right hand. And kneeling before Him they mocked Him, saying, "Hail, King of the Jews!" And they spat upon Him, and took the reed and struck Him on the head. And when they had mocked Him, they stripped Him of the robe, and put His own clothes on Him, and led Him away to crucify Him."
"As they went out, they came upon a man of Cyrene, Simon by name; this man they compelled to carry His cross [see Crosses]. And when they came to a place called Golgotha, which means the place of a skull [shown in the photograph above], they offered Him wine to drink, mingled with gall; but when He tasted it, He would not drink it."
"And when they had crucified Him, they divided His garments among them by casting lots; then they sat down and kept watch over Him there. And over His head they put the charge against Him, which read, "This is Jesus the King of the Jews." Then two robbers were crucified with Him, one on the right and one on the left. And those who passed by derided Him, wagging their heads and saying, "You who would destroy the Temple [see Temples] and build it in three days, save yourself! If you are the Son of God, come down from the cross."
"So also the chief priests, with the scribes and elders, mocked Him, saying, "He saved others; He cannot save Himself. He is the King of Israel; let him come down now from the cross, and we will believe in Him. He trusts in God; let God deliver Him now, if He desires Him; for He said, 'I am the Son of God.'" And the robbers who were crucified with Him also reviled Him in the same way."
"Now from the sixth hour there was darkness over all the land until the ninth hour. And about the ninth hour Jesus cried with a loud voice, "Eloi, Eloi, Lama Sabachthani?" that is, "My God, My God, why hast Thou forsaken Me?"
"And some of the bystanders hearing it said, "This man is calling Elijah."
"And one of them at once ran and took a sponge, filled it with vinegar, and put it on a reed, and gave it to Him to drink. But the others said, "Wait, let us see whether Elijah will come to save Him."
"And Jesus cried again with a loud voice and yielded up His spirit." (Matthew 27:27-50 RSV)
Fact Finder: As He was being crucified, Jesus Christ was twice offered a drink, one of which He refused, another which He accepted. What were those two drinks with different ingredients?