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:9:36 –

Indeed, the number of months with Allah is twelve ˹lunar˺ months in the register of Allah ˹from˺ the day He created the heavens and the earth; of these, four are sacred. That is the correct religion, so do not wrong yourselves during them. And fight against the disbelievers collectively as they fight against you collectively. And know that Allah is with the righteous ˹who fear Him˺.  

Verily the number of months, used to reckon the year, with God is twelve months in the Book of God, the Preserved Tablet (al-lawh al-mahfūz), from the day that He created the heavens and the earth; four of them, that is, the months, are sacred, inviolable: Dhū’l-Qa‘da, Dhū’l-Hijja, Muharram and Rajab. That, making of them sacred, is the right, the upright, religion. So do not wrong yourselves during them, during these sacred months, with acts of disobedience, for their burden ˹of sin˺ is greater therein; but it is also said to mean ˹do not wrong yourselves˺ at any time during all the months ˹of the year˺. And fight the idolaters altogether, all of them, throughout the months, even as they fight you altogether; and know that God is with those who fear Him, supporting and assisting ˹them˺.
القرآن:٩:٣٦ –

إِنَّ عِدَّةَ الشُّهُورِ عِنْدَ اللَّهِ اثْنَا عَشَرَ شَهْرًا فِي كِتَابِ اللَّهِ يَوْمَ خَلَقَ السَّمَاوَاتِ وَالْأَرْضَ مِنْهَا أَرْبَعَةٌ حُرُمٌ ۚ ذَٰلِكَ الدِّينُ الْقَيِّمُ ۚ فَلَا تَظْلِمُوا فِيهِنَّ أَنْفُسَكُمْ ۚ وَقَاتِلُوا الْمُشْرِكِينَ كَافَّةً كَمَا يُقَاتِلُونَكُمْ كَافَّةً ۚ وَاعْلَمُوا أَنَّ اللَّهَ مَعَ الْمُتَّقِينَ  

{إن عدة الشهور} المعتد بها للسنة {عند الله اثنا عشر شهرا في كتاب الله} اللوح المحفوظ {يوم خلق السماوات والأرض منها} أي الشهور {أربعة حرم} محرَّمة ذو القعدة وذو الحجة والمحرم ورجب {ذلك} أي تحريمها {الدين القيم} المستقيم {فلا تظلموا فيهن} أي الأشهر الحرم {أنفسكم} بالمعاصي فإنها فيها أعظم وزرا وقيل في الأشهر كلها {وقاتلوا المشركين كافة} جميعا في كل الشهور {كما يقاتلونكم كافة واعلموا أن الله مع المتقين} بالعون والنصر.