John Gill Commentary Exodus 5:22

"And Moses returned unto Jehovah, and said, Lord, wherefore hast thou dealt ill with this people? why is it that thou hast sent me?" — Exodus 5:22 (ASV)

And Moses returned to the Lord. Bishop Patrick thinks that this not only intimates that the Lord had appeared to Moses since he came into Egypt, but that there was some settled place where he appeared, and where he might resort to him on all occasions, and therefore is said to return to him; though it may signify no more than that, instead of staying to give an answer to the officers, which he might be at a loss to do, he went to God, to the throne of grace, by prayer, as he was accustomed to do in cases of difficulty.

and said, Lord, why have you so evil treated this people? or afflicted them, and suffered them to be thus afflicted; which to ascribe to God was right, whatever were the means or instruments; for all afflictions are of him, and who has always wise reasons for what he does, as he now had; to try the faith and patience of his people; to make the Egyptians more odious to them, and so take them off from following their manners, customs, rites, and superstitions, and make them more desirous of departing from there to the land of Canaan, nor seek a return to Egypt again; and that his vengeance on the Egyptians for such cruelty and inhumanity might appear the more just, and his power might be seen in the plagues he inflicted on them, and in the deliverance of his people when reduced to the utmost extremity.

why is it that you have sent me? he seems to wish he had never been sent, and could be glad to be recalled, something of the same disposition still remaining in him as when first called; since no end was achieved by his mission, no deliverance accomplished, indeed, the people were more afflicted and oppressed than before; and therefore he was at a loss how to account for it that he should be sent at all, seeing nothing came of it to the good of the people.