Safwan ibn 'Abdullah ibn Safwan, who was married to the daughter of Abu'd-Darda', said, "I visited them in Syria and found Umm ad-Darda' in the house, but not Abu'd-Darda'. She asked, 'Are you intending to go on hajj this year?' 'Yes,' I replied. She said, 'Make supplication to Allah and ask for good for us. The Prophet ﷺ said, "The supplication of a Muslim man for his absent brother is answered. At his head there is a guardian angel. Whenever he asks Allah to give his brother good, the angel says, 'Amen, and may you have the same.'"' I met Abu'd-Darda' in the market and he said something similar which was related from the Prophet, may Allah bless him and grant him peace."

حَدَّثَنَا مُحَمَّدُ بْنُ سَلاَمٍ، قَالَ: حَدَّثَنَا يَحْيَى بْنُ أَبِي غَنِيَّةَ، قَالَ: أَخْبَرَنَا عَبْدُ الْمَلِكِ بْنُ أَبِي سُلَيْمَانَ، عَنْ أَبِي الزُّبَيْرِ، عَنْ صَفْوَانَ بْنِ عَبْدِ اللهِ بْنِ صَفْوَانَ، وَكَانَتْ تَحْتَهُ الدَّرْدَاءُ بِنْتُ أَبِي الدَّرْدَاءِ، قَالَ: قَدِمْتُ عَلَيْهِمُ الشَّامَ، فَوَجَدْتُ أُمَّ الدَّرْدَاءِ فِي الْبَيْتِ، وَلَمْ أَجِدْ أَبَا الدَّرْدَاءِ، قَالَتْ: أَتُرِيدُ الْحَجَّ الْعَامَ؟ قُلْتُ: نَعَمْ، قَالَتْ: فَادْعُ اللَّهَ لَنَا بِخَيْرٍ، فَإِنَّ النَّبِيَّ ﷺ كَانَ يَقُولُ: إِنَّ دَعْوَةَ الْمَرْءِ الْمُسْلِمِ مُسْتَجَابَةٌ لأَخِيهِ بِظَهْرِ الْغَيْبِ، عِنْدَ رَأْسِهِ مَلَكٌ مُوَكَّلٌ، كُلَّمَا دَعَا لأَخِيهِ بِخَيْرٍ قَالَ: آمِينَ، وَلَكَ بِمِثْلٍ، قَالَ: فَلَقِيتُ أَبَا الدَّرْدَاءِ فِي السُّوقِ فَقَالَ مِثْلَ ذَلِكَ، يَأْثُرُ عَنِ النَّبِيِّ ﷺ.