Albert Barnes on Luke 22:28

My temptations. My trials, my humiliations, and my assaults from the power of Satan and a wicked world.

And I appoint unto you a kingdom. He assures them here that they should have a kingdom--their expectations would be realized. They had continued with him; they had seen how he had lived, and to what trials he had been subjected; they had all along expected a kingdom, and he assures them that they should not be disappointed.

As my Father, &c. They had seen how God had appointed a kingdom to him. It was not with pomp, and splendour, and external glory, but it was in poverty, want, persecution, and trial. So would he appoint to them a kingdom. They should surely possess it; but it would be not with external splendour, but by poverty and toil. The original word appoint has the force of a covenant or compact, and means that it should be surely or certainly done, or that he pledged himself to do it. All Christians must enter into the kingdom of heaven after the manner of their Lord--through much tribulation; but, though it must be, as it was with him, by many tears and sorrows, yet they shall surely reach the place of their rest and the reward of heaven, for it is secured to them by the covenant pledge and faithfulness of their Lord and King.

(p) "my temptations" He 4:15