The Jews then said to him, "What sign have you to show us for doing this?" Jesus answered them, "Destroy this temple, and in three days I will raise it up." The Jews then said, "It has taken forty-six years to build this temple, and will you raise it up in three days?" But he spoke of the temple of his body. When therefore he was raised from the dead, his disciples remembered that he had said this; and they believed the scripture and the word which Jesus had spoken.
Now when he was in Jerusalem at the Passover feast, many believed in his name when they saw the signs which he did; but Jesus did not trust himself to them, because he knew all men and needed no one to bear witness of man; for he himself knew what was in man. - John 2:18-25
When the Jews asked Jesus what sign He gave to them that He was acting with God's authority, He answered: "Destroy this temple, and in three days I will raise it up." The Jews thought He meant the Temple of Jerusalem, but He referred to the temple of His Body.
There were doubtless some who asked in good faith why Christ took upon Himself the work of reforming the abuse which had crept into the Temple, but others who asked in a spirit of hatred and ill-will. See our Lord's wisdom. His answer is one which would set the former thinking, but only perplex the latter, and render their ill-will greater. This is always God's way. He proposes mysteries for the acceptance of all; men of good-will ponder on them and are drawn to God; men of ill-will reject the mystery and its Author.
Our Lord made the Resurrection the test and corner-stone of His Mission. So the Apostles preached Jesus and the Resurrection. So Saint Paul says: "If Christ is not risen, our faith is vain." It is the test of a Christian: Do you believe that Jesus rose again? Thank God for your firm belief in this glorious mystery, and cry out, Lord, I believe!
Christ speaks of His Body as the temple of God consecrated to His service. So, too, our bodies are the temples of God. How sacred they ought to be in our eyes! How carefully we should guard them against any defilement of intemperance or impurity, even against a dangerous look, an immodest word, or an unbecoming gesture.
- taken from The Ministry of Jesus Christ: Short Meditations on the Public Life of Our Lord, by Father Richard Frederick Clarke, SJ