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:8:15 –

O you who have believed, when you meet those who disbelieve advancing ˹for battle˺, do not turn to them your backs ˹in flight˺.  

O you who believe, when you encounter the disbelievers inching forward, that is, amassed, advancing slowly because of their large numbers, do not turn your backs to them, fleeing.
القرآن:٨:١٥ –

يَا أَيُّهَا الَّذِينَ آمَنُوا إِذَا لَقِيتُمُ الَّذِينَ كَفَرُوا زَحْفًا فَلَا تُوَلُّوهُمُ الْأَدْبَارَ  

{يا أيها الذين آمنوا إذا لقيتم الذين كفروا زحفا} أي مجتمعين كأنهم لكثرتهم يزحفون {فلا تولُّوهم الأدبار} منهزمين.