To All: Siddhis are not restricted to the vedic literature. We find similar feats in the gospels and stories of Christian saints. These siddhis can be considered as samadhi which is a byproduct of meditation.
The Christian gospels do not talk so much of meditation as the vedic literature does. But the gospels do talk much about faith in one's teacher or beliefs. This faith is equivalent to meditation, a practice that attempts to transcend thoughts and reason. What did it mean for someone to walk on water? At the very least, the gospel writers were saying that the person had control of the elements of water and the air. In other words, the person had control over his appetite and sexual urges. In can interpreted that water represents the sense of taste, and air represents the sense of touch or sexual urge. At best, the writers were saying that the person actually did the seemingly impossible by hovering over the water. Thus, we read that St. Peter was able to walk on water as he approached Jesus, but started to sink when he doubted his faith. JR