Quran 2, Al-Baqara (The Cow) ⓘ

2:26Lo! Allah disdaineth not to coin the similitude even of a gnat. Those who believe know that it is the truth from their Lord; but those who disbelieve say: What doth Allah wish (to teach) by such a similitude? He misleadeth many thereby, and He guideth many thereby; and He misleadeth thereby only miscreants;

إِنَّ اللَّهَ لَا يَسْتَحْيِي أَنْ يَضْرِبَ مَثَلًا مَا بَعُوضَةً فَمَا فَوْقَهَا فَأَمَّا الَّذِينَ آمَنُوا فَيَعْلَمُونَ أَنَّهُ الْحَقُّ مِنْ رَبِّهِمْ وَأَمَّا الَّذِينَ كَفَرُوا فَيَقُولُونَ مَاذَا أَرَادَ اللَّهُ بِهَذَا مَثَلًا يُضِلُّ بِهِ كَثِيرًا وَيَهْدِي بِهِ كَثِيرًا وَمَا يُضِلُّ بِهِ إِلَّا الْفَاسِقِينَ