The word "if" packs a punch in our readings today! Is Jesus' identity up for debate? I think not. So why does both the devil and those who deride Him put his identity into question? Because if He is who He says He is - that means we have to go to Him with our spiritual hunger - and the Devil doesn't want that, nor do those who want others to worship them.
This is a bit of a longer-than-usual homily - but I felt that since it is such a huge topic, I'd need a little extra time to unpack it.