(a) Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) reported: I spent a night at the house of my maternal aunt, the Mother of the Believers Sayyidah Maymunah (may Allah be pleased with her). I lay across the width of the pillow, and the Messenger of Allah (peace and blessings be upon him) and his wife lay along its length. The Messenger of Allah (peace and blessings be upon him) slept, and when it was midnight, or a little before or after it, the Messenger of Allah (peace and blessings be upon him) woke up and began rubbing the sleep from his face with his hand. Then he recited the last ten verses of Surah Al Imran, then went to a hanging water-skin and performed ablution from it thoroughly, then stood and prayed. And he mentioned the rest of the hadith.
(b) Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: I saw him (peace and blessings be upon him) stand up and use the miswak, then perform ablution while he was reciting these verses: "Indeed, in the creation of the heavens and the earth and the alternation of night and day are signs for those of understanding" [Surah Al Imran: 190], until he completed the surah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 420
It is narrated from Muhammad bin Sirin (may Allah have mercy on him) that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) was reciting among some people. Meanwhile he got up to relieve himself, then came back and began reciting. A man said to him: O Commander of the Believers! You have not performed ablution and you are reciting? Umar bin al-Khattab (may Allah be pleased with him) said: Who gave you this fatwa?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 421
Abd al-Rahman bin Yazid (may Allah have mercy on him) said: We were with Sayyiduna Salman (may Allah be pleased with him) on a journey. He went apart from the people and relieved himself, then came back. We said to him: O Abu Abdullah! Perform ablution, perhaps we will ask you about some verses of the Qur'an. He said: "Ask, for I am not touching it, and 'None touch it except the purified' [Surah al-Waqi'ah: 79]." So we asked him, and he recited the Qur'an to us before performing ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 422
Abu al-Gharif said that Sayyiduna Ali (may Allah be pleased with him) said: There is no harm in your reciting the Qur'an without ablution, but if you are junub, then you may not recite even a single letter.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 423