Hadithcore
Al-Adab Al-Mufrad, 768
sahih· Al-Albani

Abu'l-Harith al-Kirmani heard a man say to Abu Raja', "I greet you and I ask Allah to join both of us together in the Abiding Abode of His mercy." Abu Raja' said, "Is anyone capable of that?" He continued, "What is the Abiding Abode of His mercy?" "The Garden," the man replied. "That is not correct," he said. The man asked, "Then what is the Abiding Abode of His mercy?" "The Lord of the Worlds," he replied.

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ قَالَ‏:‏ حَدَّثَنِي أَبُو الْحَارِثِ الْكَرْمَانِيُّ قَالَ‏:‏ سَمِعْتُ رَجُلاً قَالَ لأَبِي رَجَاءٍ‏:‏ أَقْرَأُ عَلَيْكَ السَّلاَمَ، وَأَسْأَلُ اللَّهَ أَنْ يَجْمَعَ بَيْنِي وَبَيْنَكَ فِي مُسْتَقَرِّ رَحْمَتِهِ، قَالَ‏:‏ وَهَلْ يَسْتَطِيعُ أَحَدٌ ذَلِكَ‏؟‏ قَالَ‏:‏ فَمَا مُسْتَقَرُّ رَحْمَتِهِ‏؟‏ قَالَ‏:‏ الْجَنَّةُ، قَالَ‏:‏ لَمْ تُصِبْ، قَالَ‏:‏ فَمَا مُسْتَقَرُّ رَحْمَتِهِ‏؟‏ قَالَ‏:‏ قُلْتُ‏:‏ رَبُّ الْعَالَمِينَ‏.‏

References2 variants
In-Book Reference
Book 33, Hadith 15
English Reference
Book 33, Hadith 768