Sayyiduna Khuzaymah bin Thabit (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) fixed for us permission to wipe for three days; and had we asked him for more, he (peace and blessings be upon him) would have given us more.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3742