Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) narrates that two men set out on a journey. The time of prayer came and they had no water with them, so they performed dry ablution (tayammum) with clean earth and prayed. Then they found water while the time was still in. One of them repeated the ablution and the prayer, while the other did not. Then they came to the Messenger of Allah (peace and blessings be upon him) and told him what had happened. He (peace and blessings be upon him) said to the one who had not repeated: "You acted according to the Sunnah, and your prayer suffices you." And he said to the one who had performed ablution and repeated: "For you there is a double reward." This hadith is sahih (authentic) on the condition of Imam Bukhari and Imam Muslim, because Abdullah bin Nafi' is reliable (thiqah) and he narrated this chain from al-Layth as connected, whereas others narrated it as mursal.