John 20:8

He saw and believed. He did not yet believe that Jesus was risen from the dead, because he was still ignorant that he was to rise from the dead. For although the apostles had so often heard their divine Master speak in the most plain terms of his resurrection, still being so much accustomed to parables, they did not understand, and imagined something else was meant by these words. (St. Augustine, tract. 120. in Joan.)

(3.) See how Peter's boldness encouraged John; now he took heart and ventured in (v. 8), and he saw and believed; not barely believed what Mary said, that the body was gone (no thanks to him to believe what he saw), but he began to believe that Jesus was risen to life again, though his faith, as yet, was weak and wavering.

Verses 1-10 If Christ gave his life a ransom, and had not taken it again, it would not have appeared that his giving it was accepted as satisfaction. It was a great trial to Mary, that the body was gone. Weak believers often make that the matter of complaint, which is really just ground of hope, and matter of joy. It is well when those more honoured than others with the privileges of disciples, are more active than others in the duty of disciples; more willing to take pains, and run hazards, in a good work. We must do our best, and neither envy those who can do better, nor despise those who do as well as they can, though they come behind. The disciple whom Jesus loved in a special manner, and who therefore in a special manner loved Jesus, was foremost. The love of Christ will make us to abound in every duty more than any thing else. He that was behind was Peter, who had denied Christ. A sense of guilt hinders us in the service of God. As yet the disciples knew not the Scripture; they Christ must rise again from the dead.