Once Imam Ali (a) travelled with one of the Jews of Khaybar. On the way, they arrived at a river which had a great width and there was no bridge or vehicle by which they could pass the river, while the Jew did not know Imam Ali (a).
The Jew whispered something and walked on the water and crossed the river. Then, he turned to Imam Ali (a) and said, “if you knew what I know, you would cross the river like I did without being drowned.”
Imam Ali (a) said, “O Jew! Stay where you are, so that I come to you.” Then, he (a) thought of God and by God’s permission, walked on water and crossed the river. The Jew was surprised and begged Imam Ali (a) on the knees that, “O young one! What did you say that water became hard like rock beneath your feet and moved here from there?!” Imam (a) asked him, “what did you say to walk on water and cross? (Imam Ali (a) asked him to say first in order to clarify the issue)
The Jew said, “I called God in the honor of the great vicegerent of Muhammad (s). God favored me and I crossed water.”
Imam Ali (a) said, “I am that vicegerent of Muhammad (s).”
The Jew said, “Indeed, you tell the truth”, and accepted Islam at the presence of Imam Ali (a).
Source:
(1) Safinat al-Bihar, p. 648.
