Al-Allaamah Ahmad Bin Yahyah An-Najmi (rahimahullaah) said:
Know that the truth is that which (has been revealed by) Allaah and (given to) His Messenger (sallal-laahu-alayhi-wasallam) in the Book and the Sunnah, even if its adherents and those who embrace it are few. What came in the Islamic legislation is the truth, which a (person) is commanded to follow, even if the majority of the people free themselves from it and those who follow it are few.
Allaah (Glorified Be He) stated:
ثُمَّ جَعَلْنَاكَ عَلَىٰ شَرِيعَةٍ مِنَ الْأَمْرِ فَاتَّبِعْهَا وَلَا تَتَّبِعْ أَهْوَاءَ الَّذِينَ لَا يَعْلَمُونَ
إِنَّهُمْ لَنْ يُغْنُوا عَنْكَ مِنَ اللَّهِ شَيْئًا ۚ وَإِنَّ الظَّالِمِينَ بَعْضُهُمْ أَوْلِيَاءُ بَعْضٍ ۖ وَاللَّهُ وَلِيُّ الْمُتَّقِينَ
‘’Then We have put you (O Muhammad) on a plain way of (Our) commandment [like the one which We commanded Our Messengers before you (i.e. legal ways and laws of the Islamic Monotheism)]. So follow you that (Islamic Monotheism and its laws), and follow not the desires of those who know not. Verily, they can avail you nothing against Allah (if He wants to punish you). Verily, the Zalimun (polytheists, wrong-doers, etc.) are Auliya’ (protectors, helpers, etc.) to one another, but Allah is the Wali (Helper, Protector, etc.) of the Muttaqun (pious).’’ [Al-Jaathiya: Aayaat 18-19]
Therefore, O slave of Allaah! Be eager to follow the truth; follow the straight path and the path of early pious predecessors-the companions of the Messenger (sallal-laahu-alayhi-wasallam)-and do not feel lonely due to the small numbers of those who follow it and the large numbers of those who oppose it; for indeed Ibraaheem (alayhis-salaam) was an Imaam on his own and with Allaah lies all success.
[Source: Irshaad As-Saaree Fee Sharh Sunnah Lil-Barbahaaree page: 47. Abridged & slightly paraphrased]