Sayyiduna Hudhaifah (may Allah be pleased with him) narrates that when the Prophet (peace and blessings of Allah be upon him) would wake up at night for Tahajjud, he would clean his blessed mouth with a miswak. Janab Harun and Abu Husayn have narrated in their version these words: "When he (peace be upon him) would get up and perform Tahajjud."