Ayatal Kursi

Narrated Abu Huraira:
Allah's Messenger (ﷺ) ordered me to guard the Zakat revenue of Ramadan. Then somebody came to me and started stealing from the foodstuff. I caught him and said, "I will take you to Allah's Messenger (ﷺ)!" Then Abu Huraira described the whole narration and said: That person said (to me), "(Please don't take me to Allah's Messenger (ﷺ) and I will tell you a few words by which Allah will benefit you.) When you go to your bed, recite Ayat-al-Kursi, (2.255) for then there will be a guard from Allah who will protect you all night long, and Satan will not be able to come near you till dawn." (When the Prophet (ﷺ) heard the story) he said (to me), "He (who came to you at night) told you the truth although he is a liar; and it was Satan."
Sahih al-Bukhari 5010

-- Bismillaahir Rahmaanir Raheem

Allahu laaa ilaaha illaa huwal haiyul qai-yoom; laa taakhuzuhoo sinatunw wa laa nawm; lahoo maa fissamaawaati wa maa fil ard; man zallazee yashfa'u indahooo illaa be iznih; ya'lamu maa baina aideehim wa maa khalfahum; wa laa yuheetoona beshai 'immin 'ilmihee illa be maa shaaaa; wasi'a kursiy yuhus samaa waati wal arda wa la ya'ooduho hifzuhumaa; wa huwal aliyyul 'azeem

"Allah! There is no god but He - the Living, The Self-subsisting, Eternal. No slumber can seize Him Nor Sleep. His are all things In the heavens and on earth. Who is there can intercede In His presence except As he permitteth? He knoweth What (appeareth to His creatures As) Before or After or Behind them. Nor shall they compass Aught of his knowledge Except as He willeth. His throne doth extend Over the heavens And on earth, and He feeleth No fatigue in guarding And preserving them, For He is the Most High. The Supreme (in glory)."

-- Narrated 'Abdullah bin Mas'ud:
"Allah has not created in the heavens nor in the earth what is more magnificent than Ayat Al-Kursi." Sufyan said: "Because Ayat Al-Kursi is the Speech of Allah, and Allah's Speech is greater than Allah's creation of the heavens and the earth."
Jami at-Tirmidhi 288