John 2:22

When therefore he was raised from the dead, his disciples remembered that he spake this; and they believed the Scripture and the word which Jesus had said.

As Westcott declared:

John notices on other occasions the real meaning of the words of the Lord not understood at first: John 7:39; 12:33; 21:19; and, in each case, he speaks with complete authority. This trait of progressive knowledge is inexplicable except as a memorial of personal experience.[20]

And they believed the scripture ... The Scripture in view here is John 2:19, above, where Jesus had spoken of raising up the destroyed temple.