Our Saviour refuseth to give them any sign, but that of his resurrection the third day from the dead. This was the sign to which he afterwards refers the Pharisees, Matthew 12:39 Luke 11:29. Our Saviour's words must not be understood as commanding or licensing them to destroy him, but as foretelling what they would do. It is in Scripture very ordinary to use the imperative mood for the future tense of the indicative; see Genesis 42:18 Deuteronomy 32:50 Isaiah 8:9,10 Isaiah 54:1 1 Thessalonians 13:27. Destroy, is as much as, I know you will destroy, or, If you do destroy this temple, I will build it up in three days. The resurrection of Christ from the dead is ordinarily in Scripture attributed to the Father; but here Christ saith he would do it; and the Spirit, by whom he is said to have been quickened, equally proceedeth both from the Father and the Son. Nor is this the only text where it is attributed to Christ; see 1 Thessalonians 20:17,18. It was the work of the Trinity, out of itself, and so the work of all the three Persons. These words were three years after this made a great charge against Christ, Matthew 26:61; but they reported them thus, This fellow said, I am able to destroy the temple of God, and to build it in three days. He said only, this temple, meaning his body.
Related Commentaries of John 2:19
John 2:19
19 Jesus answered and said unto them,Destroy this temple, and in three days I will raise it up.