A.T. Robertson Commentary Mark 14:36

"And he said, Abba, Father, all things are possible unto thee; remove this cup from me: howbeit not what I will, but what thou wilt." — Mark 14:36 (ASV)

Abba, Father (Αββα ο πατηρ). Both Aramaic and Greek and the article with each. This is not a case of translation, but the use of both terms as is Ga 4:6, a probable memory of Paul's childhood prayers. About "the cup" see on Mt 26:39. It is not possible to take the language of Jesus as fear that he might die before he came to the Cross. He was heard (Hebrews 5:7f.) and helped to submit to the Father's will as he does instantly.

Not what I will (ου τ εγω θελω). Matthew has "as" (ως). We see the humanity of Jesus in its fulness both in the Temptations and in Gethsemane, but without sin each time. And this was the severest of all the temptations, to draw back from the Cross. The victory over self brought surrender to the Father's will.