Sura al-Baqara 2:204

وَمِنَ ٱلنَّاسِ مَن يُعْجِبُكَ قَوْلُهُۥ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَيُشْهِدُ ٱللَّـهَ عَلَىٰ مَا فِى قَلْبِهِۦ وَهُوَ أَلَدُّ ٱلْخِصَامِ

wa-mina l-nāsi man yuʿjibuka qawluhu fī l-ḥayāti l-dunyā wa-yushhidu allāha ʿalā mā fī qalbihi wa-huwa aladdu l-khiṣāmi

There is the type of man whose speech about this world's life May dazzle thee, and he calls Allah to witness about what is in his heart; yet is he the most contentious of enemies.