I came to Sham and went to Abu Darda's house, but I did not find him there. I found Umm Darda instead, and she asked, "Do you intend to make the pilgrimage this year?"I replied, "Yes."She said, "Then pray to Allah for good on our behalf, for the Prophet ﷺ used to say, 'The supplication of a Muslim for his brother in his absence is answered. At his head is an angel appointed to him, and whenever he prays for good for his brother, the appointed angel says, Amen, and may you have the like.'"He said, "I then went out to the market and met Abu Darda, who told me the same thing, narrating it from the Prophet ﷺ."
قدمت الشام، فأتيت أبا الدرداء في منزله فلم أجده، ووجدت أم الدرداء، فقالت: أتريد الحج العام؟ فقلت: نعم قالت: فادع الله لنا بخير، فإن النبي ﷺ كان يقول: دعوة المسلم لأخيه بظهر الغيب مستجابة، عند رأسه ملك موكل، كلما دعا لأخيه بخير قال الملك الموكل به: آمين، ولك بمثل قال: فخرجت إلى السوق فلقيت أبا الدرداء، فقال لي مثل ذلك يرويه عن النبي ﷺ.
Muslim narrated it in Kitab al-Dhikr wal-Dua (2733) from Ishaq bin Ibrahim, who said, Isa bin Yunus informed us, Abdul-Malik bin Abu Sulayman narrated to us, from Abu Zubayr, from Safwan bin Abdullah bin Safwan, and he related it.Similar in meaning is what was narrated from Abdullah bin Amr bin As, that the Messenger of Allah ﷺ said, "The prayer most quickly answered is the prayer of one who is absent for another who is absent." Abu Dawud (1535), Tirmidhi (1980), and Bukhari in Adab al-Mufrad (623) all narrated it through various routes from Abdul-Rahman bin Ziyad bin Anam, from Abu Abdul-Rahman Abdullah bin Yazid, from Abdullah bin Amr bin As, and he related it.Tirmidhi said, "This is a gharib hadith, we do not know it except from this route, and Afriqi is considered daif in hadith, he being Abdul-Rahman bin Ziyad bin Anam."I say, it is as he said, for Abdul-Rahman bin Ziyad bin Anam, Afriqi, its judge, is daif by the agreement of the scholars. Ibn Hibban said, "He narrates fabricated reports from trustworthy narrators and practices tadlis."As for what was narrated from Anas, who said, the Prophet ﷺ, when he prayed earnestly for someone, would say, "May Allah place upon you the prayer of righteous people, who stand at night and fast by day, who are neither sinners nor wrongdoers," the correct view is that this is mawquf.Abd bin Humayd narrated it (1360) from Muslim bin Ibrahim, who said, Hammad bin Salama narrated to us, from Thabit, from Anas, and he related it. Ibn Ammar al-Shahid stated decisively in his Ilal that this is a mistake on the part of Abd bin Humayd, and that the correct version is that it is mawquf. The mawquf version was narrated by Bukhari in Adab al-Mufrad (631), Bazzar (6530), Ibn Sunni in Amal al-Yawm wal-Layla (203), and others, through multiple chains from Anas.