Indeed, the number of months with Allah is twelve [lunar] months in (9:36)

﴿إِنَّ عِدَّةَ الشُّهُورِ عِندَ اللَّهِ اثْنَا عَشَرَ شَهْرًا فِي كِتَابِ اللَّهِ يَوْمَ خَلَقَ السَّمَاوَاتِ وَالْأَرْضَ مِنْهَا أَرْبَعَةٌ حُرُمٌ ۚ ذَٰلِكَ الدِّينُ الْقَيِّمُ ۚ فَلَا تَظْلِمُوا فِيهِنَّ أَنفُسَكُمْ ۚ وَقَاتِلُوا الْمُشْرِكِينَ كَافَّةً كَمَا يُقَاتِلُونَكُمْ كَافَّةً ۚ وَاعْلَمُوا أَنَّ اللَّهَ مَعَ الْمُتَّقِينَ﴾
[ التوبة: 36]

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].

There are twelve months of the year decreed by Allah, no more or less, which Allah established in the Preserved Tablet when He created the heavens and the earth.
Of these twelve months, four are sacred, during which Allah has forbidden fighting.
Three of them consecutive ( Dhū Al-Qa‘dah, Dhū Al-Ḥijjah and Muḥarram ), and one is on its own ( Rajab ).
The twelve months of the year, and respecting the sacredness of four of them, is the correct way of life.
Allah tells the believers not to wrong themselves during these sacred months by fighting, violating their sacredness.
Also, the believers are instructed to fight the idolaters all together as they fight them all together, and to know that Allah is with those who are Mindful, who follow what He instructs and stay away from what He has prohibited, and He helps and supports them.
If Allah supports anyone, no one will be able to defeat them.

Verily, the number of months with Allah is twelve months (in a year), so was it ordained by Allah on the Day when He created the heavens and the earth; of them four are Sacred, (i.e. the 1st, the 7th, the 11th and the 12th months of the Islamic calendar). That is the right religion, so wrong not yourselves therein, and fight against the Mushrikun (polytheists, pagans, idolaters, disbelievers in the Oneness of Allah) collectively, as they fight against you collectively. But know that Allah is with those who are Al-Muttaqun (the pious - see V. 2:2).

phonetic Transliteration

Inna AAiddata alshshuhoori AAinda Allahi ithna AAashara shahran fee kitabi Allahi yawma khalaqa alssamawati waalarda minha arbaAAatun hurumun thalika alddeenu alqayyimu fala tathlimoo feehinna anfusakum waqatiloo almushrikeena kaffatan kama yuqatiloonakum kaffatan waiAAlamoo anna Allaha maAAa almuttaqeena

Abdullah Yusuf Ali - Translation

The number of months in the sight of Allah is twelve (in a year)- so ordained by Him the day He created the heavens and the earth; of them four are sacred: that is the straight usage. So wrong not yourselves therein, and fight the Pagans all together as they fight you all together. But know that Allah is with those who restrain themselves.

Safi-ur-Rahman al-Mubarakpuri

Verily, the number of months with Allah is twelve months (in a year), so was it ordained by Allah on the Day when He created the heavens and the earth; of them four are sacred. That is the right religion, so wrong not yourselves therein, and fight against the Mushrikin idolaters collectively as they fight against you collectively. But know that Allah is with those who have Taqwa.

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