The Sorrowful Mysteries of the Rosary present Jesus at His most human. He prays for deliverance, He is whipped and mocked, He is burdened by a cross, He is killed. What god can bleed? What god can die?
Only a God who has become like us in all things but sin.
In His passion, Jesus does nothing beyond the strength of anyone acting in His name. Even the angel who appears does nothing but comfort Him. Even the power of the Name, "I AM," is unveiled for only an instant. The few words He speaks at His trials, when silence is not the better part of wisdom, are simple declarations of Who Jesus is.
It is in His passion and death, in His most human moment, that Jesus triumphs -- a triumph only possible because He is the Son of the Most High. His humanity is made perfect through obedience, but obedience meant the Passion only because He was God's Son. The Cross is a triumph we celebrate only because it is the triumph of a man, and it is a triumph only because that man is God.