Mukhtasar Bukhari

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "When any one of you performs ablution, he should put water into his nose and then clean it, and whoever uses stones for istinja, he should do so with an odd number (of stones), and when any one of you wakes up from his sleep, he should wash his hand before putting it into the water for ablution, because none of you knows where his hand has been (on which parts of his body it has passed) during the night."