Abd al-Rahman bin Abi al-Zinad narrates from his father (may Allah have mercy on him) that he said: I saw several of our jurists who held this view; among them were Sa'id bin al-Musayyab (may Allah have mercy on him), the seven jurists of Madinah (may Allah have mercy on them) and some others, who used to say: "Whoever performs tayammum and prays, then finds water, whether the time of the prayer remains or has passed, in any case he is not required to repeat the prayer. He will perform ablution and ritual bath (ghusl) for the coming prayers, and tayammum for major ritual impurity (janabah) and for ablution are the same."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1099