The "heart" was considered to be what enabled a person to make decisions. AT: "your minds are slow to believe" or "you are slow to believe" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Jesus uses a question to remind the disciples about what the prophets said. AT: "It was necessary ... glory" (See: [[rc://en/ta/man/translate/figs-rquestion]])