Matthew 9:5 - Ellicott's Commentary On The Whole Bible

Whether is easier,...? — The form of the question implies what we call an argument à fortiori. It was easier to say, “Thy sins are forgiven thee,” for those words could not be put to any outward test, and only the consciousness of the sinner could attest their power. It was a bolder and a harder thing to risk the utterance of words which challenged an immediate and visible fulfilment; and yet He was content to utter such words, without fear of the result. Measured in their true relation to each other, the spiritual wonder was, of course, the greater; but here, as so often elsewhere, He puts Himself, as it were, on the level of those who hear Him, and vouchsafes to speak to them according to their thoughts.