Matthew 27:30-33, Mark 15:19-22, Luke 23:26, John 19:17.
They spit on him, and struck him on the head again and again. After they had mocked him, they took off the robe and put his own clothes on him. Then they led him away to crucify him. As they were going out, they met a man from Cyrene, named Simon, and they forced him to carry the cross. They came to a place called Golgotha (which means The Place of the Skull).
In John 19:17, it says, "Carrying his own cross,". It seems Jesus could not keep carrying it because he already suffered a lot by the soldiers.