Al-Mukhtasar
أُو۟لَـٰٓئِكَ ٱلَّذِينَ ٱشْتَرَوُا۟ ٱلضَّلَـٰلَةَ بِٱلْهُدَىٰ فَمَا رَبِحَت تِّجَـٰرَتُهُمْ وَمَا كَانُوا۟ مُهْتَدِينَ ﴿١٦﴾
It is they who are the fools, because they exchanged faith for disbelief; and this exchange did not help them in any way, because they lost their faith in Allah and lost the way to the truth.