Muwatta Imam Malik (Riwayat Ibn al-Qasim)

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that indeed the Messenger of Allah (peace and blessings be upon him) used to teach him this supplication just as he would teach a surah of the Qur'an. The Prophet (peace and blessings be upon him) said: «اللهم إني أعوذ بك من عذاب جهنم، وأعوذ بك من عذاب القبر، وأعوذ بك من فتنة المسيح الدجال، وأعوذ بك من فتنة المحيا والممات.» "O my Allah! I seek refuge in You from the punishment of Hell, and I seek refuge in You from the punishment of the grave, and I seek refuge in You from the trial of the False Messiah (Dajjal), and I seek refuge in You from the trials of life and death."