Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: "The Messenger of Allah (peace and blessings be upon him) forbade cauterisation, and he disliked drinking hot water; and when he applied kohl he applied it an odd number of times, and when he cleaned himself after relieving himself he used an odd number of stones."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15003