Majma al-Zawaid 11265 — Surah al-Sajdah, and the words of Allah

Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him) that he said (that is, he recited this verse: Allah Almighty says:) "Their sides forsake their beds; they call upon their Lord in fear and hope." The Prophet (peace and blessings be upon him) said: "This refers to the servant standing (in prayer) at night (that is, offering voluntary prayers)."
Ahmad recorded it; the narrator named Shahr did not meet Sayyiduna Mu'adh (may Allah be pleased with him), and there is weakness in this narrator, though he has also been declared trustworthy. The remaining narrators of this narration are thiqat (trustworthy).