John 20:8

8. He saw, and believed Believed what? Some say he believed just what he saw, namely, that the sepulchre was empty by the absence of the body. But this is making the apostle say a very insipid thing. The word believe is often used by the apostle without an object expressed, to designate some advance in embracing the main truths of Christianity. See notes on John 2:11; John 2:22; John 14:29. That he was fully convinced of the resurrection of Christ by what he saw, as he had not previously been by the understanding of the Scriptures, is clearly implied by the next verse. But while John was convinced, Peter, though John does not say it, is amazed and sorely perplexed at the strange concurrence of events. See Luke 24:12.