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quran:2:26 –

Indeed, Allah is not timid to present an example - that of a mosquito or what is smaller than it. And those who have believed know that it is the truth from their Lord. But as for those who disbelieve, they say, "What did Allah intend by this as an example?" He misleads many thereby and guides many thereby. And He misleads not except the defiantly disobedient,  

God is not ashamed to strike, to make, a similitude (mathal: is the first direct object; mā either represents an indefinite noun described by what comes after it and constitutes a second direct object, meaning ‘whatever that similitude may be’; or it ˹the mā˺ is extra to emphasise the vileness ˹involved˺, so that what follows constitutes the second direct object); even of a gnat, (ba‘ūda is the singular of ba‘ūd), that is, small flies; or anything above it, that is, larger than it, so that this explanation is not affected ˹by the size of the creature˺ with regard to the judgement ˹God is making˺; as for the believers, they know it, the similitude, is the truth, established and given in this instance, from their Lord; but as for disbelievers, they say, ‘What did God desire by this for a similitude?’ (mathalan is a specification, meaning, ‘by this similitude’; mā is an interrogative of rejection and is the subject; dhā means alladhī, whose relative clause contains its predicate, in other words, ‘what use is there in it?’). God then responds to them saying: Thereby, that is, by this similitude, He leads many astray, from the truth on account of their disbelieving in it, and thereby He guides many, believers on account of their belief in it; and thereby He leads none astray except the wicked, those that reject obedience to Him.
القرآن:٢:٢٦ –

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 بِهَٰذَا مَثَلًا ۘ يُضِلُّ بِهِ كَثِيرًا وَيَهْدِي بِهِ كَثِيرًا ۚ وَمَا يُضِلُّ بِهِ إِلَّا الْفَاسِقِينَ  

{إن الله لا يستحيي أن يضرب} يجعل {مثلا} مفعول أول {ما} نكرة موصوفة بما بعدها مفعول ثان أيَّ مثل كان أو زائدة لتأكيد الخسة فما بعدها المفعول الثاني {بعوضة} مفرد البعوض وهو صغار البق {فما فوقها} أي أكبر منها أي لا يترك بيانه لما فيه من الحكم {فأما الذين آمنوا فيعلمون أنه} أي المثل {الحق} الثابت الواقع موقعه {من ربِّهم وأما الذين كفروا فيقولون ماذا أراد الله بهذا مثلاً} تمييز أي بهذا المثل، وما استفهام إنكار مبتدأ، وذا بمعنى الذي بصلته خبره أي: أيّ فائدة فيه قال الله تعالى في جوابهم {يضل به} أي بهذا المثل {كثيراً} عن الحق لكفرهم به {ويهدي به كثيراً} من المؤمنين لتصديقهم به {وما يضل به إلا الفاسقين} الخارجين عن طاعته.

See similar narrations below:

Collected by Dārimī
darimi:3395 – Muḥammad b. ʿAbdullāh al-Raqāshī > Yazīd b. Zurayʿ > Saʿīd > Qatādah > In Allāh Lā Yastaḥyī

[Machine] "To strike a likeness with a mosquito or anything above it. As for those who believe, they know that it is the truth from their Lord. And as for those who disbelieve, they say, 'What does Allah mean by this example?' He misleads many thereby, and guides many thereby. And He only misleads the defiantly disobedient." [Al-Baqarah: 26] He said, "That is to say, they know that it is the speech of the Most Merciful."  

الدارمي:٣٣٩٥ – أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ الرَّقَاشِيُّ عَنْ يَزِيدَ بْنِ زُرَيْعٍ عَنْ سَعِيدٍ عَنْ قَتَادَةَ قَالَ {إِنَّ اللَّهَ لَا يَسْتَحْيِي

أَن يَضْرِبَ مَثَلًا مَا بَعُوضَةً فَمَا فَوْقَهَا فَأَمَّا الَّذِينَ آمَنُوا فَيَعْلَمُونَ أَنَّهُ الْحَقُّ مِن رَّبِّهِمْ وَأَمَّا الَّذِينَ كَفَرُوا فَيَقُولُونَ مَاذَا أَرَادَ اللهُ بِهَذَا مَثَلاً يُضِلُّ بِهِ كَثِيرًا وَيَهْدِي بِهِ كَثِيرًا وَمَا يُضِلُّ بِهِ إِلَّا الْفَاسِقِينَ} [البقرة 26] قَالَ أَيْ يَعْلَمُونَ أَنَّهُ كَلَامُ الرَّحْمَنِ