The Messenger of Allah ﷺ said, "There is no Muslim servant who prays for his brother in his absence except that the angel says, 'And the same for you.'"
قال رسول الله ﷺ: ما من عبد مسلم يدعو لأخيه بظهر الغيب إلا قال الملك: ولك بمثل.
Muslim reported it in the chapter on remembrance and supplication (2732), on the authority of Ahmad bin Umar bin Hafs Waqii, who said, Muhammad bin Fudayl narrated to us, from his father, from Talha bin Ubaydullah bin Kurayz, from Umm Darda, from Abu Darda, who said, and he mentioned it.