Hadith: Abu Sālih used to order us that if anyone of us wanted to sleep, he should lie on his right side

عن سهيل، قال: كان أبو صالح يأمرنا، إذا أراد أحدُنا أن ينامَ، أن يضطجعَ على شِقِّه الأيمن، ثم يقول: «اللهم ربَّ السماواتِ وربَّ الأرض وربَّ العرش العظيم، ربَّنا وربِّ كلِّ شيء، فالقَ الحَبِّ والنَّوى، ومُنْزِلَ التوراة والإنجيل والفُرقان، أعوذ بك من شرِّ كل شيء أنت آخذٌ بناصيتِه، اللهم أنت الأولُ فليس قبلك شيء، وأنت الآخرُ فليس بعدك شيء، وأنت الظاهرُ فليس فوقك شيء، وأنت الباطن فليس دونك شيء، اقضِ عنَّا الدِّينَ، وأغنِنا من الفقر» وكان يروي ذلك عن أبي هريرة، عن النبي صلى الله عليه وسلم .
[صحيح] - [رواه مسلم]

Suhayl reported: Abu Sālih used to order us that if anyone of us wanted to sleep, he should lie on his right side, and then say: "O Allah, Lord of the heavens and Lord of the earth and Lord of the Magnificent Throne! Our Lord, and the Lord of everything, the Cleaver of grains and date seeds, the Revealer of the Torah, the Gospel, and the Criterion (the Qur'an), I seek refuge with You from the evil of everything that You have grasp of its forelock (You have full control over it). O Allah, You are the First, there is nothing before You, You are the Last and there is nothing after You, You are the Highest and there is nothing above You, and You are the Nearest and there is nothing nearer than You. Remove the burden of debt from us and relieve us of poverty." Abu Sālih used to narrate this from Abu Hurayrah, who narrated it from the Prophet (may Allah's peace and blessings be upon him).
Sahih/Authentic. - [Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) used to order his Companions that if any of them wanted to sleep, he should lie on t his right side and then say: "O Allah, Lord of the heavens and Lord of the earth and Lord of the Magnificent Throne! Our Lord, and the Lord of everything", i.e. O Allah the Lord of the heavens and the earth, their Creator and their Owner and the One who raises the creation, the Lord, Owner and Creator of the Great and Magnificent Throne, the Creator of all human beings, their Owner and their Nurturer, and the Lord of everything. "The Cleaver of grains and date seeds", i.e. O Allah the One who splits them and brings forth from them plants and date palm trees. Grains and date seeds are mentioned in particular here because of their excellence, or because of their abundance in the land of the Arabs. "The Revealer of the Torah, the Gospel, and the Criterion", i.e. O Allah the One who revealed the Torah to Mūsa, the Gospel to ‘Īsa, and the Qur'an to Muhammad. "I seek refuge with You from the evil of everything that You have grasp of its forelock (You have full control over it)", i.e. I flee to You and seek refuge with You from the evil of all creatures, because all of them are under Your authority, Your power and control. "O Allah, You are the First, there is nothing before You, You are the Last and there is nothing after You, You are the Highest and there is nothing above You, and You are the Nearest and there is nothing nearer than You", the Prophet (may Allah's peace and blessings be upon him) clearly explained these four names of Allah. "The First" means that everything other than Him is created after being non-existent. This makes it obligatory for the slave to observe the favor of his Lord in every religious and worldly blessing. This is because the cause and the result are all from Allah, the Almighty. "The Last" means that Allah is the only One who will remain, and everything else will perish. He is also the Self-Sufficient to whom all creatures turn in worship, with hope and fear, and ask Him for whatever they need. "The Highest" indicates the greatness of His attributes, and that all things, including entities and attributes, are of no worth when compared to His greatness. It also indicates Allah's real superiority and elevation over all of His creatures. "The Nearest" indicates Allah's knowledge of all secrets, consciences, everything hidden and concealed, and subtle matters. It also indicates Allah's perfect closeness and nearness. There is no conflict between the Highest and the Nearest, because there is no one similar to Allah in His attributes. He is high in His nearness, and near in His elevation. "Remove the burden of debt from us and relieve us of poverty", i.e. the Prophet (may Allah's peace and blessings be upon him) asked Allah, Exalted, to relieve him of his debts and grant him sufficiency against poverty.