سنن النسائي

It was narrated from Abu Sa'eed that two men performed Tayammum and prayed, then they found water when there was still time left for prayer. One of them performed Wudu' and repeated the prayer, and the other did not. They asked the Prophet (ﷺ) about that and he said to the one who did not repeat the prayer: "You followed the Sunnah and your prayer is acceptable." And he said to the other: "And you will have something like the reward of two prayers."