Ibn al-Qayyim reported: Abdullah Ibn Mas’ud, may Allah be pleased with him, said, “The united community is that which adheres to the truth, even if you are alone.”
Nuaym ibn Hammad said, “If the community becomes corrupted, you must adhere to its practice before it became corrupt. Even if you are alone, you by yourself would be the united community.”
Source: I’lām al-Muwaqqi’īn 3/308
عن ابن القيم قال عبد الله بن مسعود رضي الله عنه الْجَمَاعَةُ مَا وَافَقَ الْحَقَّ وَإِنْ كُنْت وَحْدَك
وَقَالَ نُعَيْمُ بْنُ حَمَّادٍ إذَا فَسَدَتْ الْجَمَاعَةُ فَعَلَيْك بِمَا كَانَتْ عَلَيْهِ الْجَمَاعَةُ قَبْلَ أَنْ تَفْسُدَ وَإِنْ كُنْت وَحْدَك فَإِنَّك أَنْتَ الْجَمَاعَةُ حِينَئِذٍ
3/308 إعلام الموقعين عن رب العالمين