For as yet they knew not the scripture. — This explains in what sense it was that St. John now believed. Up to this time they knew not the meaning of the Scripture which foretold the Resurrection; but from that moment at least they recognised in the fact of the absent body of Christ the truth that He must rise again. (Comp. Notes on John 2:21-22.)
That he must rise again from the dead. — Comp. especially Notes on Luke 24:26; Luke 24:44.