Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says that when the Messenger of Allah (peace and blessings be upon him) stood at night, he would pray tahajjud.
(b) Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says that when the Prophet (peace and blessings be upon him) got up at night, he would pray tahajjud and say: 'Allahumma lakal-hamdu, anta nurus-samawati wal-ardi wa man fihinn' (O Allah! All praise is for You; You are the Light of the heavens, the earth and all that is in them). 'Wa lakal-hamdu, anta qayyimus-samawati wal-ardi wa man fihinn' (All praise is for You; You are the Sustainer of the heavens, the earth and all that is in them). 'Wa lakal-hamdu, anta malikus-samawati wal-ardi wa man fihinn, wa lakal-hamd' (All praise is for You; You are the King of the heavens, the earth and all that is in them, and all praise is for You). 'Antal-haqq, wa wa'dukal-haqq, wa liqa'uka haqq, wa qawluka haqq, wal-jannatu haqq, wan-naru haqq, wan-nabiyyuna haqq, wa Muhammadun (peace and blessings be upon him) haqq, was-sa'atu haqq' (You are the Truth, Your promise is true, Your word is true and meeting You is true; Paradise, Hell, the Hour, Muhammad (peace and blessings be upon him) and the prophets are all true). 'Allahumma laka aslamtu, wa bika amantu, wa 'alayka tawakkaltu, wa ilayka anabtu, wa bika khasamtu, wa ilayka hakamtu' (O Allah! To You I have submitted, in You I have believed, in You alone I place my trust, and to You I turn in humility; by You I dispute, and to You I refer for judgement). 'Faghfir li ma qaddamtu wa ma akhkhartu wa ma asrartu wa ma a'lantu' (Forgive me my earlier and later sins, and forgive all that I have committed in secret and openly). 'Antal-muqaddimu wa antal-mu'akhkhiru, la ilaha illa anta, aw la ilaha ghayruk' (You are the One who brings forward and You are the One who puts back; there is no god besides You, or he said: there is no god other than You (a difference in wording)).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4665
Tawus says that he heard Sayyiduna Ibn Abbas (may Allah be pleased with them both) say that when the Messenger of Allah (peace and blessings be upon him) prayed tahajjud at night, he would say: 'Allahumma lakal-hamdu, anta nurus-samawati wal-ard, wa lakal-hamdu, anta qayyimus-samawati wal-ardi wa man fihinn, antal-haqq, wa wa'dukal-haqq, wa qawlukal-haqq, wa liqa'uka haqq, wal-jannatu haqq, wan-naru haqq, wan-nabiyyuna haqq. Allahumma laka aslamtu, wa bika amantu, wa 'alayka tawakkaltu, wa ilayka anabtu, wa ilayka khasamtu, wa ilayka hakamtu, faghfir li ma qaddamtu wa ma akhkhartu wa ma asrartu wa ma a'lantu, anta ilahi, la ilaha illa ant' (O Allah! Praise is for You; You are the Light of the heavens and the earth. All praise is for You alone; You manage the heavens, the earth and all that is in them. You are the Truth, and Your promise, Your word and meeting You are true; Paradise, Hell and the prophets are also true. O Allah! I submit to You, I believe in You, in You I place my trust and to You I turn in humility; to You I bring my disputes and to You I refer for judgement. Forgive me all my earlier and later sins, and forgive all the sins I have committed in secret or openly. You alone are my God; I have no god besides You).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4666
Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever wakes up at night and says: 'La ilaha illallahu wahdahu la sharika lah, lahul-mulku wa lahul-hamd, wa huwa 'ala kulli shay'in qadir, subhanallah, walhamdu lillah, wa la ilaha illallah, wallahu akbar, wa la hawla wa la quwwata illa billah' (There is no god but Allah, alone, without partner; His is the dominion and His is all praise, and He has power over all things. Glory be to Allah, all praise is for Allah, there is no god but Allah, Allah is the Greatest, and there is no power to turn away from evil and no strength to do good except by Allah's enabling), and then says: 'Rabbighfir li' (My Lord! Forgive me), he is forgiven." Or he said: "Then he supplicates and his supplication is answered; and if he resolves, gets up, performs ablution and prays, his prayer is accepted."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4667