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]. (IT)
App reference (IT): Book 17, Hadith 30 (IT)
Arabic/English book reference (IT): Book 17, Hadith 1494 (IT)