Here are these two disciples; they are obviously pious Jews. There are so many children of Israel in the New Testament who are not earnest believers.
Do we remember, those who walk with Christ, when it first dawned on us, when we first heard believingly and the Holy Spirit so worked in our minds that we grasped that this was true? Do we remember that first moment we really understood there is reconciliation with God? There is salvation. There is a Saviour who has come from heaven and died on Calvary to bear the punishment of my sin. Salvation, new life, the forgiveness of all my sin, walking with God, knowing him, having access to him in prayer, being certain of heaven, belonging to him. These things astonished us too.