Riyad as-Saliheen 1494
Abud-Darda' (May Allah be pleased with him) reported:
I heard the Messenger of Allah ﷺ saying, "Whenever a Muslim supplicates for his (Muslim) brother in his absence, the angels say: 'May the same be for you too'."
[Muslim].
وعن أبي الدرداء رضي الله عنه أنه سمع رسول الله ﷺ يقول:
"ما من عبد مسلم يدعو لأخيه بظهر الغيب إلا قال الملك ولك بمثل" ((رواه مسلم)).
Classification
Sahih (Authentic)
References
Riyad as-Saliheen 1494
Riyad as-Saliheen Book of Du'a (Supplications), Hadith 30