SHAHIH BUKHARI | Jilid 2 | Bab 19

According to the Statement of Allah تعالى: The bedouins say, 'We believe,' Say (O Muhammad ﷺ), 'You believe not but you only say we have surrendered (in Islam).'” (V.49:14)

And if they had embraced Islam truly (sincerely) their Islam would have been as is referred to in the Statement of Allah جل جلاله: "Truly, the religion with Allah is Islam." (V.3:19). "And whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be one of the losers.” (V.3:85).

لِقَوْلِهِ تَعَالَى: {قَالَتِ الأَعْرَابُ آمَنَّا قُلْ لَمْ تُؤْمِنُوا وَلَكِنْ قُولُوا أَسْلَمْنَا}. فَإِذَا كَانَ عَلَى الْحَقِيقَةِ فَهُوَ عَلَى قَوْلِهِ جَلَّ ذِكْرُهُ: {إِنَّ الدِّينَ عِنْدَ اللَّهِ الإِسْلاَمُ}، {وَمَنْ يَبْتَغِ غَيْرَ الإِسْلاَمِ دِينًا فَلَنْ يُقْبَلَ مِنْهُ}