Al-Jawāb as-Sahīh li-man baddala dīn al-Masīh - Ibn Taimiya - (2/378)

He—exalted is He—also says:

“Fight those who do not believe in Allah or in the Last Day, who do not forbid what Allah and His Messenger have forbidden, and who do not embrace the religion of truth—among the People of the Scripture—until they pay the jizyah with their own hands while humbled.” ⦗9:29⦘

The Prophet—may Allah bless him and grant him peace—personally set out to confront them in the year of Tabuk. He rallied all the believers for that campaign and did not allow anyone who was able to fight to remain behind. Whoever stayed back because he did not deem fighting them obligatory was a disbeliever; if he outwardly professed Islam, then he was a hypocrite under divine curse. Allah declared that He would never forgive such people and forbade His Prophet to perform the funeral prayer for them. Regarding this, He revealed most of Surah Baraʾah (al-Tawbah), as established by mass-transmitted reports, making plain the disbelief of those who had asked the Prophet for permission to stay behind instead of marching with him to fight the Christians.

He—exalted is He—also said:

وَقَالَ - تَعَالَى -: {قَاتِلُوا الَّذِينَ لَا يُؤْمِنُونَ بِاللَّهِ وَلَا بِالْيَوْمِ الْآخِرِ وَلَا يُحَرِّمُونَ مَا حَرَّمَ اللَّهُ وَرَسُولُهُ وَلَا يَدِينُونَ دِينَ الْحَقِّ مِنَ الَّذِينَ أُوتُوا الْكِتَابَ حَتَّى يُعْطُوا الْجِزْيَةَ عَنْ يَدٍ وَهُمْ صَاغِرُونَ} [التوبة: ٢٩] وَقَدْ خَرَجَ النَّبِيُّ - صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ - لِقِتَالِهِمْ بِنَفْسِهِ عَامَ تَبُوكَ وَاسْتَنْفَرَ لِقِتَالِهِمْ جَمِيعَ الْمُؤْمِنِينَ وَلَمْ يَأْذَنْ لِأَحَدٍ مِنَ الْقَادِرِينَ عَلَى الْغَزْوِ فِي التَّخَلُّفِ وَمَنْ تَخَلَّفَ لِأَنَّهُ لَمْ يَرَ قِتَالَهُمْ وَاجِبًا كَانَ كَافِرًا وَإِنْ أَظْهَرَ الْإِسْلَامَ كَانَ مُنَافِقًا مَلْعُونًا بَيَّنَ اللَّهُ أَنَّهُ لَا يَغْفِرُ لَهُمْ وَنَهَى نَبِيَّهُ عَنِ الصَّلَاةِ عَلَيْهِمْ وَأَنْزَلَ فِي ذَلِكَ جُمْهُورَ سُورَةِ بَرَاءَةَ بِالنَّقْلِ الْمُتَوَاتِرِ حَتَّى بَيَّنَ كُفْرَ الَّذِينَ اسْتَأْذَنُوهُ فِي تَرْكِ الْخُرُوجِ مَعَهُ لِقِتَالِ النَّصَارَى. قَالَ - تَعَالَى -: