وَإِذَا جَآءُوكُمۡ قَالُوٓاْ ءَامَنَّا وَقَد دَّخَلُواْ بِٱلۡكُفۡرِ وَهُمۡ قَدۡ خَرَجُواْ بِهِۦۚ وَٱللَّهُ أَعۡلَمُ بِمَا كَانُواْ يَكۡتُمُونَ

Wa izaa jaaa'ookum qaalooo aamannaa wa qad dakhaloo bilkufri wa hum qad kharajoo bih; wallaahu a'lamu bimaa kaanoo yaktumoon

When they come to thee, they say: "We believe": but in fact they enter with a mind against Faith, and they go out with the same but Allah knoweth fully all that they hide.

— Al-Mai'dah (ٱلْمَائِدَة), 5:61