Appears 2 times in the Quran.
2:204 وَمِنَ ٱلنَّاسِ مَن يُعْجِبُكَ قَوْلُهُۥ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَيُشْهِدُ ٱللَّهَ عَلَىٰ مَا فِى قَلْبِهِۦ وَهُوَ أَلَدُّ ٱلْخِصَامِ
And among men is he whose speech about the life of this world causes you to wonder, and he calls on Allah to witness as to what is in his heart, yet he is the most violent of adversaries.
19:97 فَإِنَّمَا يَسَّرْنَٰهُ بِلِسَانِكَ لِتُبَشِّرَ بِهِ ٱلْمُتَّقِينَ وَتُنذِرَ بِهِۦ قَوْمًا لُّدًّا
So We have only made it easy in your tongue that you may give good news thereby to those who guard (against evil) and warn thereby a vehemently contentious people.