فَاِنْ اٰمَنُوْا بِمِثْلِ مَآ اٰمَنْتُمْ بِهٖ فَقَدِ اهْتَدَوْا ۚوَاِنْ تَوَلَّوْا فَاِنَّمَا هُمْ فِيْ شِقَاقٍۚ فَسَيَكْفِيْكَهُمُ اللّٰهُ ۚوَهُوَ السَّمِيْعُ الْعَلِيْمُ ۗ ( البقرة: ١٣٧ )
Fa in aamanoo bimisli maaa aamantum bihee faqadih tadaw wa in tawallaw fa innamaa hum fee shiqaaq; fasayakfeekahumul laah; wa Huwas Samee'ul Aleem (al-Baq̈arah 2:137)
So if they believe in the same as you believe in, then they have been [rightly] guided; but if they turn away, they are only in dissension, and Allah will be sufficient for you against them. And He is the Hearing, the Knowing. (Al-Baqarah  : 137)
1 Mufti Taqi Usmani
So, if they believe in the same way as you believe, they will have certainly found the right path, and if they turn away, then the fact is that they are in antagonism. Then Allah will suffice you against them, and He is the All-Hearing, the All-Knowing.