Quran Al-Qasas 28:53
وَإِذَا يُتۡلَىٰ عَلَيۡهِمۡ قَالُوٓاْ ءَامَنَّا بِهِۦٓ إِنَّهُ ٱلۡحَقُّ مِن رَّبِّنَآ إِنَّا كُنَّا مِن قَبۡلِهِۦ مُسۡلِمِينَ ٥٣
Translation
And when it is recited to them, they say, "We have believed in it; indeed, it is the truth from our Lord. Indeed we were, [even] before it, Muslims [i.e., submitting to Allāh]."