Sayyiduna al-Hajjaj bin Amr al-Mazini (may Allah be pleased with him) said: "The Messenger of Allah (peace and blessings be upon him) used to pray tahajjud after his sleep, and he used to use the miswak before praying tahajjud."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3202