John Gill

He went away again the second time,.... To the same place as before, or at some little distance; after he had reproved his disciples for their sleeping, and had exhorted them to watchfulness and prayer, suggesting the danger they were liable to, and the condition they were in: and prayed, saying, O my Father, if this cup may not pass away from me except I drink it, thy will be done. The sense of this prayer to his God and Father is, that if his sufferings and death could not be dispensed with; if it was not consistent with the decrees of God, and the covenant of grace, that he should be excused from them; or if the glory of God, and the salvation of his people required it, that he must drink up that bitter cup, he was content to do it; desiring in all things to submit unto, and to fulfil his Father's will, though it was so irksome and disagreeable to nature.