John Lightfoot on John 2:19

[Destroy this Temple.] I. Christ showeth them no sign that was a mere sign, Matthew 12:39. The turning of Moses' rod into a serpent, and returning the serpent into a rod again; the hand becoming leprous, and restored to its proper temperament again; these were mere signs; but those wonders which Moses afterward wrought in Egypt were not mere signs, but beneficent miracles; and whoever would not believe upon those infinite miracles which he wrought, would much less have believed upon mere signs. And, indeed, it was unbecoming our blessed Lord so far to indulge to their obstinate incredulity, to be showing new signs still at every beck of theirs, who would not believe upon those infinite numbers he put forth upon every proper occasion.

II. Matthew 12:39,40. When they had required a sign, Christ remits them to the sign of the prophet Jonah; and he points at the very same sense in these words, Destroy this Temple, &c.: that is, "My resurrection from the dead will be a sign beyond all denial, proving and affirming, that what I do I act upon divine authority, and that I am he who is to come (Rom 1:4). Further than this you must expect no other sign from me. If you believe me not while I do such works, at least believe me when I arise from the dead."

He acted here, while he is purging the Temple, under that notion as he was the authorized Messiah, Malachi 3:1,3, and expressly calls it "his Father's house," verse 16. Show us therefore some sign, (say the Jews,) by which it may appear that thou art the Messiah the Son of God; at least, that thou art a prophet. I will show you a sufficient sign, saith Christ: destroy this temple, viz. of my body, and I will raise it from the dead again; a thing which was never yet done, nor could be done by any of the prophets.