Sura al-Qaṣaṣ 28:53

وَإِذَا يُتْلَىٰ عَلَيْهِمْ قَالُوٓا۟ ءَامَنَّا بِهِۦٓ إِنَّهُ ٱلْحَقُّ مِن رَّبِّنَآ إِنَّا كُنَّا مِن قَبْلِهِۦ مُسْلِمِينَ

wa-idhā yutlā ʿalayhim qālū āmannā bihi innahu l-ḥaqqu min rrabbinā innā kunnā min qablihi muslimīna

And when it is recited to them, they say: "We believe therein, for it is the Truth from our Lord: indeed we have been Muslims (bowing to Allah's Will) from before this.