Musannaf Ibn Abi Shaybah 8247 — Those who said he does not repeat it

Ata said: Two men became junub (in a state of major ritual impurity). They both performed tayammum and prayed. Then both found water within the time; one of them repeated the prayer, and the other was content with the prayer he had offered. This was mentioned to the Prophet (peace and blessings be upon him), and he said: "The one who repeated it will have a double reward, and the other's prayer is also valid."