Fussilat - 41:52

قُلْ أَرَأَيْتُمْ إِن كَانَ مِنْ عِندِ اللَّهِ ثُمَّ كَفَرْتُم بِهِ مَنْ أَضَلُّ مِمَّنْ هُوَ فِي شِقَاقٍ بَعِيدٍ
[41:52]
Say: Tell me if it is from Allah; then you disbelieve in it, who is in greater error than he who is in a prolonged opposition?
Say: "See ye if the (Revelation) is (really) from Allah, and yet do ye reject it? Who is more astray than one who is in a schism far (from any purpose)?"
Bethink you: If it is from Allah and ye reject it - Who is further astray than one who is at open feud (with Allah)?