وَمَن يَبۡتَغِ غَيۡرَ ٱلۡإِسۡلَٰمِ دِينٗا فَلَن يُقۡبَلَ مِنۡهُ وَهُوَ فِي ٱلۡأٓخِرَةِ مِنَ ٱلۡخَٰسِرِينَ
And whoever desires other than Islam as religion - never will it be accepted from him, and he, in the Hereafter, will be among the losers
- This is a fundamental principle as it relates to Islam and other religions. The only religion accepted by Allah is Islam after sending Muhammad Salallahualaihiwassalam.