Hadithcore
Al-Adab Al-Mufrad, 1035
sahih· Al-Albani

Abu Dharr said, "I came to the Prophet, (ﷺ), when he had finished his prayer. I was the first person to be greeted with the greeting of Islam. He said, 'And on you and the mercy of Allah. From where have you come?' I said, 'From Ghifar.'"

حَدَّثَنَا عَبْدُ اللهِ بْنُ مَسْلَمَةَ، قَالَ‏:‏ حَدَّثَنَا سُلَيْمَانُ بْنُ الْمُغِيرَةِ، عَنْ حُمَيْدِ بْنِ هِلاَلٍ، عَنْ عَبْدِ اللهِ بْنِ الصَّامِتِ، عَنْ أَبِي ذَرٍّ قَالَ‏:‏ أَتَيْتُ النَّبِيَّ صلى الله عليه وسلم حِينَ فَرَغَ مِنْ صَلاَتِهِ، فَكُنْتُ أَوَّلَ مَنْ حَيَّاهُ بِتَحِيَّةِ الإِسْلاَمِ، فَقَالَ‏:‏ وَعَلَيْكَ، وَرَحْمَةُ اللهِ، مِمَّنْ أَنْتَ‏؟‏ قُلْتُ‏:‏ مِنْ غِفَارٍ‏.‏

References2 variants
In-Book Reference
Book 42, Hadith 72
English Reference
Book 42, Hadith 1035