It is Sunnah to recite Āyat Il-Kursiy before sleeping, as it protects the Muslim from Satan until the morning.

Abu Hurayrah (ABPWH) narrated, “... Then the Prophet (PBUH) asked me, ‘What did your prisoner do last night?’ I answered, ‘He promised to teach me some words which he claimed will benefit me before Allāh, so I let him go.’ The Prophet (PBUH) asked, ‘What are those words that he taught you?’ I said, ‘He told me, “When you go to bed, recite Āyat Al-Kursiy from its beginning to its end. If you do so, a guardian will be appointed by Allāh to protect you during the night, and no devil will be able to approach you until the morning.’ The Prophet (PBUH) said, ‘Verily, he told you the truth although he is a liar. O Abā Hurayrah, do you know with whom you were speaking for the last three nights?’ I said, ‘No.’ The Prophet (PBUH) replied, ‘That was a devil.’.” (Al-Bukhāriy no. 2311)

Abu Mas‘ood Il-Ansāriy (ABPWH) narrated that Allāh’s Messenger (PBUH) said, “Whoever recites the last two verses of Soorat Il-Baqarah at night, they shall be sufficient for him.” (Al-Bukhāriy no. 4008, Muslim no. 807)

Yet, these two verses are not of the Adthkār of sleep in particular, but they are rather from the Adthkār of the night. Thus, one who did not recite them at night can recite them when he goes to bed.

The opinions of scholars varied regarding the interpretation of the meaning of the phrase “shall be sufficient for him.” Some scholars said that it means they will give him reward as if he performed voluntary night prayer (Qiyām Al-Layl). Other scholars said that it means that they will protect him against the devil. A third opinion says that it means they will protect him against anything that might harm him. An-Nawawiy, may Allāh have mercy on him, said they would bring about all of these virtues.

This is proven by the following Hadeeth:

‘Ā’ishah, may Allāh be pleased with her, said, “When the Messenger of Allāh  would go to bed every night, he would bring his hands together and blow in them, and he would recite in them Soorat Al-Ikhlās, Soorat Al-Falaq, and Soorat An-Nās, then he would wipe with them over whatever he is able to reach of his blessed body, starting at his head and face, then moving to the rest of his body. He would do this three times.” (Al-Bukhāriy no. 5017)

The following could be learnt from the previous Hadeeth:

The Prophet (PBUH) used to apply this Sunnah every night as ‘Ā’ishah, may Allāh be pleased with her, mentions, “.. every night,” and one who wants to apply this Sunnah should do it the same way the Prophet (PBUH) did.

‘Urwah Ubn Nawfal narrated through his father that the Prophet (PBUH) said to Nawfal, “Recite Soorat Al-Kāfiroon and let it be the last thing you recite before you sleep, for it clears you from Shirk (polytheism).” (Ahmad no. 21934, Abū Dāwood no. 5055 and At-Tirmidthiy no. 3403)

{ بِاسْمِكَ اللَّهُمَّ أَمُوتُ وَأَحْيَا }

“O Allāh by Your name I die and I revive.” (Al-Bukhāriy no. 6324)

{ اللَّهُمَّ خَلَقْتَ نَفْسِي وَأَنْتَ تَوَفَّاهَا، لَكَ مَمَاتُهَا وَمَحْيَاهَا، إِنْ أَحْيَيْتَهَا فَاحْفَظْهَا، وَإِنْ أَمَتَّهَا فَاغْفِرْ لَهَا، اللَّهُمَّ إِنِّي أَسْأَلُكَ الْعَافِيَةَ }

“O Allāh, You have created my soul and You take it back. Unto You is its death and its life. If You give it life then protect it, and if You cause it to die then forgive it. O Allāh, I ask You well-being.” (Muslim no. 2712)

{ اللَّهُمَّ رَبَّ السَّمَاوَاتِ وَرَبَّ الأَرْضِ وَرَبَّ الْعَرْشِ الْعَظِيمِ , رَبَّنَا وَرَبَّ كُلِّ شَيْءٍ, فَالِقَ الْحَبِّ وَالنَّوَى , وَمُنْزِلَ التَّوْرَاةِ وَالإِنْجِيلِ وَالْفُرْقَانِ , أَعُوذُ بِكَ مِنْ شَرِّ كُلِّ شَيْءٍ أَنْتَ آخِذٌ بِنَاصِيَتِهِ , اللَّهُمَّ أَنْتَ الأَوَّلُ فَلَيْسَ قَبْلَكَ شَيْءٌ , وَأَنْتَ الآخِرُ فَلَيْسَ بَعْدَكَ شَيْءٌ , وَأَنْتَ الظَّاهِرُ فَلَيْسَ فَوْقَكَ شَيْءٌ , وَأَنْتَ الْبَاطِنُ فَلَيْسَ دُونَكَ شَيْءٌ , اقْضِ عَنَّا الدَّيْنَ وَأَغْنِنَا مِنَ الْفَقْرِ }

“O Allāh, Lord of the seven heavens and Lord of the Magnificent Throne. Our Lord and the Lord of everything. Splitter of the grain and seeds, Revealer of the Torah and the Injeel and the Furqān (i.e. the Qur’ān), I seek refuge in You from every evil that You seize by the forelock. O Allāh, You are the First and nothing has come before you, and You are the Last and nothing may come after You. You are the Evident and nothing is above You, and You are the Innermost and nothing is beyond You. Remove our burdens of debt and enrich us against poverty.” (Muslim no. 2713)

{ بِاسْمِكَ رَبِّ وَضَعْتُ جَنْبِي وَبِكَ أَرْفَعُهُ إِنْ أَمْسَكْتَ نَفْسِي فَارْحَمْهَا وَإِنْ أَرْسَلْتَهَا فَاحْفَظْهَا بِمَا تَحْفَظُ بِهِ عِبَادَكَ الصَّالِحِينَ }

“With Your Name, my Lord, I laid myself down, and with Your Name I rise. If You take my soul show mercy on it, and if You send it back then protect it like You protect Your righteous slaves.” (Al-Bukhāriy no. 6302, Muslim no. 2714)

{ اللَّهُمَّ قِنِي عَذَابَكَ يَوْمَ تَبْعَثُ عِبَادَكَ }

“O Allāh, protect me against Your punishment on the day You resurrect Your slaves.” (Ahmad no. 18660)

Glorifying Allāh (saying “Subhān Allāh”) thrity three times, Praising Allāh (saying “Al-Hamdu Lillāh”) thrity three times, and saying “Allāh is Greater” (“Allāhu Akbar”) thirty four times when going to bed for sleep.

This has great virtue, and gives the body strength throughout the day.

This is proven by the following Hadeeth:

Aliy (ABPWH) narrated that Fātimah, may Allāh be pleased with her, went to the Prophet  complaining about the effect of the stone hand-mill on her hands. She heard that the Prophet had received a few servants. When she came there she did not find him, so she mentioned her problem to ‘Ā’ishah. When the Prophet came, ‘Ā’ishah informed him about that. ‘Aliy added, “So the Prophet came to us when we had gone to bed. We wanted to get up on his arrival but he said, ‘Stay where you are.’ He then came and sat between me and her and I felt the coldness of his feet on my chest. He said, ‘Shall I direct you to something better than what you have requested? When you go to bed say “Allāhu Akbar” thirty-four times, “Subhān Allāh” thirty-three times, and “Al-Hamdu Lillāh” thirty-three times, for that is far better for you than a servant.’.” (Al-Bukhāriy no. 3705, Muslim no. 2727)

In another narration, ‘Aliy (ABPWH) said, “I have never left them since I heard about them from the Prophet (PBUH).” He was asked, “Even on the night of the battle of Siffeen?” He said, “Even on the night of the battle of Siffeen.” (Al-Bukhāriy no. 5362, Muslim no. 2727)

{ اللَّهُمَّ إِنِّي أَسْلَمْتُ وَجْهِي إِلَيْكَ ، وَفَوَّضْتُ أَمْرِي إِلَيْكَ ، وَأَلْجَأْتُ ظَهْرِي إِلَيْكَ ، رَغْبَةً وَرَهْبَةً إِلَيْكَ. لاَ مَلْجَأَ وَلاَ مَنْجَا مِنْكَ إِلاَّ إِلَيْكَ, آمَنْتُ بِكِتَابِكَ الَّذِي أَنْزَلْتَ ، وَبِنَبِيِّكَ الَّذِي أَرْسَلْتَ }

“O Allāh, I submitted my face to You, entrusted my affairs to You, and relied completely on You, out of desire and fear of You. There is no resort or escape from You except with You. I believe in Your Book that You have revealed, and in Your Prophet whom You have sent.” (Al-Bukhāriy no. 247, Muslim no. 2710)

O Allāh, I submitted my face to You, entrusted my affairs to You, and relied completely on You, out of desire and fear of You.

{ سَيِّدُ الِاسْتِغْفَارِ أَنْ يَقُولَ: اللَّهُمَّ أَنْتَ رَبِّي لَا إِلَهَ إِلَّا أَنْتَ خَلَقْتَنِي وَأَنَا عَبْدُكَ وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ أَبُوءُ لَكَ بِنِعْمَتِكَ عَلَيَّ وَأَبُوءُ بِذَنْبِي فَاغْفِرْ لِي إِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ ، قَالَ: وَمَنْ قَالَهَا مِنْ النَّهَارِ مُوقِنًا بِهَا فَمَاتَ مِنْ يَوْمِهِ قَبْلَ أَنْ يُمْسِيَ فَهُوَ مِنْ أَهْلِ الْجَنَّةِ، وَمَنْ قَالَهَا مِنْ اللَّيْلِ وَهُوَ مُوقِنٌ بِهَا فَمَاتَ قَبْلَ أَنْ يُصْبِحَ فَهُوَ مِنْ أَهْلِ الْجَنَّةِ }

Shaddād Ubn Awss narrated that the Prophet (PBUH) said, “The most superior way of asking Allāh forgiveness is, ‘O Allāh, you are my Lord. There is no God worthy of worship but You. You created me and I am Your servant, and I uphold Your covenant and my promise to You to the most of my ability. I seek refuge in You from the evil I have done. I acknowledge before You Your favor upon me, and I acknowledge my sin; so forgive me, as indeed, there is none who can forgive sins except You.’.” The Prophet (PBUH) added, “Whoever peforms this supplication in the morning with firm faith in it and dies on the same day will be from the people of Paradise, and whoever peforms it in the night with firm faith and dies during the same night will be from the people of Paradise.” (Al-Bukhāriy no. 6306)

Abu d-Dardā’ (ABPWH) reported that the Prophet (PBUH) said, “Is it difficult for any one of you to recite one third of the Qur’ān in one night?” They said, “How could one recite one third of the Qur’ān (in one night)?” He replied, “{Say: He is Allāh, the One,} (i.e. Soorat Ul-Ikhlās) is equal to one third of the Qur’ān.” (Al-Bukhāriy and Muslim)