Jesus asks this question to remind the religious leaders of what they know from scripture. AT: "I know you have read it, but you do not seem to understand what ... Jacob.'" (See: [[rc://en/ta/man/translate/figs-rquestion]])
You can translate this direct quotation as an indirect quotation. AT: "God, who said to Moses that he is the God of Abraham, the God of Isaac, and the God of Jacob." (See: [[rc://en/ta/man/translate/figs-quotations]])