Jami at-Tirmidhi 3392 (sahih, al-Albani)

قَالَ أَبُو بَكْرٍ يَا رَسُولَ اللَّهِ مُرْنِي بِشَيْءٍ أَقُولُهُ إِذَا أَصْبَحْتُ وَإِذَا أَمْسَيْتُ قَالَ ‏ "‏ قُلِ اللَّهُمَّ عَالِمَ الْغَيْبِ وَالشَّهَادَةِ فَاطِرَ السَّمَوَاتِ وَالأَرْضِ رَبَّ كُلِّ شَيْءٍ وَمَلِيكَهُ أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ أَنْتَ أَعُوذُ بِكَ مِنْ شَرِّ نَفْسِي وَمِنْ شَرِّ الشَّيْطَانِ وَشِرْكِهِ قَالَ قُلْهُ إِذَا أَصْبَحْتَ وَإِذَا أَمْسَيْتَ وَإِذَا أَخَذْتَ مَضْجَعَكَ ‏"‏ ‏.‏

“Abu Hurairah, may Allah be pleased with him, said:“Abu Bakr said: ‘O Messenger of Allah, command me with something that I may say when I reach morning and evening.’ He said: ‘Say: “O Allah Knower of the Unseen and the Seen, Originator of the heavens and the earth, Lord of everything and its Possessor, I bear witness that there is none worthy of worship except You, I seek refuge from You from the evil of my soul and from the evil of Shaitan and his Shirk (Allāhumma `ālimal-ghaibi wash-shahādati fāṭiras-samāwāti wal-arḍ, rabba kulli shai’in wa malīkahu, ash-hadu an lā ilāha illā anta, a`ūdhu bika min sharri nafsī wa min sharrish-shaiṭāni washirkihi).’” He said: ‘Say it when you reach morning, and evening, and when you go to bed.’””