Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:39:28 –

˹It is˺ an Arabic Qur'an, without any deviance that they might become righteous.  

an Arabic Qur’ān (qur’ānan ‘arabiyyan, a circumstantial qualifier for emphasis) without any deviation, that is, ˹without˺ any contradiction or variance, that perhaps they may guard themselves, against disbelief.
القرآن:٣٩:٢٨ –

قُرْآنًا عَرَبِيًّا غَيْرَ ذِي عِوَجٍ لَعَلَّهُمْ يَتَّقُونَ  

{قرآنا عربيا} حال مؤكدة {غير ذي عوج} أي لبس واختلاف {لعلهم يتقون} الكفر.