Musnad Ahmad

Once, Sayyiduna Abu Bakr Siddiq (may Allah be pleased with him) submitted in the court of the Messenger of Allah (peace and blessings be upon him): O Messenger of Allah! Teach me a supplication which I may recite in the morning and evening. The Prophet (peace and blessings be upon him) said: Recite this, «اللَّهُمَّ عَالِمَ الْغَيْبِ وَالشَّهَادَةِ ، فَاطِرَ السَّمَوَاتِ وَالْأَرْضِ ، رَبَّ كُلِّ شَيْءٍ وَمَلِيكَهُ ، أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا أَنْتَ ، أَعُوذُ بِكَ مِنْ شَرِّ نَفْسِي ، وَمِنْ شَرِّ الشَّيْطَانِ وَشِرْكِهِ» "O Allah! Creator of the heavens and the earth, Knower of the unseen and the seen, Sustainer and Owner of everything! I bear witness that there is no deity except You. I seek refuge in You from the evil of my own self, from the evil of Satan and his polytheism." And he instructed him to recite this supplication in the morning, evening, and when lying down on the bed.