What sign ... - What "miracle" dost thou work? He assumed the character of a prophet. He was reforming, by his "authority," the temple. It was natural to ask by what authority this was done; and as they had been accustomed to miracles in the life of Moses, and Elijah, and the other prophets, so they demanded evidence that he had authority thus to cleanse the house of God.

Seeing that thou doest - Rather "by what title or authority thou doest these things." Our translation is ambiguous. They wished to know "by what miracle" he had shown, or could show, his right to do those things.

What sign showest thou - See on Matthew 12:38 (note); Matthew 16:1 (note). When Moses came to deliver Israel, he gave signs, or miracles, that he acted under a Divine commission. What miracle dost thou work to show us that thou art vested with similar authority?

Then answered the Jews, and said unto him,.... They did not lay hands on him, or offer any violence to him; they did not, as the inhabitants of Nazareth did, thrust him out, and lead him to a precipice, to cast him down headlong; nor did they take up stones to stone him, as they afterwards did, when he asserted his deity: and it is surprising, that they did not rise up and destroy him at once, a single man, unarmed, and without assistance, having so highly provoked them; the restraint upon them must be his almighty power: nor do they deny what he suggested, that they had made his Father's house an house of merchandise; nor do they offer to vindicate their profanation of the temple, or object to the purging of it; only demand a proof of his right to do it: and which demand was made, not by the common people, or by the sellers of oxen, sheep, and doves, and the money changers, who were drove out, and had not spirit to rally again; but by the chief priests and elders, the sanhedrim of the nation, who had the care and government of the temple, and under whose authority the above persons acted; and whose gain and worldly interest were promoted hereby, as a like demand was afterwards made by the same persons; see Matthew 21:23;

what sign shewest thou unto us, seeing thou dost these things? they argued, that either he did these things of himself, by his own authority, and then they must be deemed rash and unjustifiable; or he did it by the authority of others: they knew it was not by theirs, who were the great council of the nation, from whom he should have had his instructions and orders, if he acted by human authority; and if he pretended to a divine authority, as they supposed he did, then they insisted upon a sign or miracle to be wrought, to prove that God was his Father, as he suggested; and that he was the proprietor and owner of the temple, and had a right to purge it, as he had done; see 1 Corinthians 1:22.

Answered

Often used in reply to an objection or criticism, or to something present in another's mind, as John 19:7, or John 3:3, where Jesus answers with reference to the error in Nicodemus' mind, rather than in direct reply to his address.

Destroy this temple (λύσατε τὸν ναὸν τοῦτον)

Destroy, Literally, loosen. Wyc., undo. See on Mark 13:2; see on Luke 9:12; see on Acts 5:38. Notice that the word for temple is ναὸν, sanctuary (see on John 2:14). This temple points to the literal temple, which is truly a temple only as it is the abode of God, hence sanctuary, but with a typical reference to Jesus' own person as the holy dwelling-place of God who "was in Christ." Compare 1 Corinthians 3:16, 1 Corinthians 3:17. Christ's death was therefore the pulling down of the temple, and His resurrection its rebuilding. The imperative in destroy is of the nature of a challenge. Compare fill ye up, Matthew 23:32.

{5} Then answered the Jews and said unto him, What {h} sign shewest thou unto us, seeing that thou doest these things?

(5) Against those who so bind God to an ordinary calling, which they themselves most shamefully abuse, that they will not admit of an extraordinary calling, which God confirms from heaven (and they would have it extinguished, although in vain) unless it is sealed with outward and bodily miracles.

(h) With what miracle do you confirm it, that we may see the heavenly power and strength which gives you authority to speak and to act in this manner?

2:18 What sign? The Jewish officials demand some sign that would demonstrate that he had authority over the temple.

2:18 Then answered the Jews - Either some of those whom he had just driven out, or their friends: What sign showest thou? - So they require a miracle, to confirm a miracle!

18-22. What sign showest thou unto us, seeing that thou doest these things?-Though the act and the words of Christ, taken together, were sign enough, they were unconvinced: yet they were awed, and though at His very next appearance at Jerusalem they "sought to kill Him" for speaking of "His Father" just as He did now (Joh 5:18), they, at this early stage, only ask a sign.

2:12-22 The first public work in which we find Christ engaged, was driving from the temple the traders whom the covetous priests and rulers encouraged to make a market-place of its courts. Those now make God's house a house of merchandise, whose minds are filled with cares about worldly business when attending religious exercises, or who perform Divine offices for love of gain. Christ, having thus cleansed the temple, gave a sign to those who demanded it, to prove his authority for so doing. He foretells his death by the Jews' malice, Destroy ye this temple; I will permit you to destroy it. He foretells his resurrection by his own power; In three days I will raise it up. Christ took again his own life. Men mistake by understanding that according to the letter, which the Scripture speaks by way of figure. When Jesus was risen from the dead, his disciples remembered he has said this. It helps much in understanding the Divine word, to observe the fulfilling of the Scriptures.