Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: Once, two men set out on a journey. The time for prayer came upon them. They did not have any water, so both of them performed tayammum with clean earth. Then, during the time of that prayer, they found water. One of them performed ablution and repeated the prayer, while the other did not repeat the prayer. Then both of them presented themselves before the Prophet (peace and blessings of Allah be upon him) and mentioned this matter to him. The Prophet (peace and blessings of Allah be upon him) said to the one who did not repeat the prayer: "You did right, your prayer is valid." And to the other who performed ablution and repeated the prayer, he said: "You will have double the reward." In narrating this tradition from the narrator named Layth, the narrator named Abdullah bin Nafi' is unique. Ibn Mubarak and other hadith scholars have narrated the opposite of this.