Musannaf Ibn Abi Shayba 3:5655

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Layth ibn Sa’d, from Bakr ibn Suwadah, from ‘Ata ibn Yasar, that two men were afflicted with janabah (major ritual impurity), so they performed tayammum and prayed. Then they found water within the time (of the prayer). One of them repeated (the prayer) and the other did not repeat it. That was mentioned to the Prophet, peace and blessings of Allah be upon him, and he said: "As for the one who repeated it, he has its reward twice. And as for the other, his prayer has sufficed him."