In the name of Allah, the Gracious, the Merciful
It is not permissible for a Muslim to desire a fight with the enemies of Islam, nor is it permissible to fight for the sake of zeal, anger, revenge, or hatred.
On the legal level, it is not lawful for a Muslim to start a fight, to initiate a war, or to attack non-combatant civilians.
وَقَاتِلُوا فِي سَبِيلِ اللَّهِ الَّذِينَ يُقَاتِلُونَكُمْ وَلَا تَعْتَدُوا إِنَّ اللَّهَ لَا يُحِبُّ الْمُعْتَدِينَ
Fight in the way of Allah those who fight you, but do not transgress. Verily, Allah does not love transgressors.
Surah al-Baqarah 2:190
However, the prohibition goes even further to the spiritual level. It is not lawful for a Muslim to have the desire to fight the enemy in his heart.
Abdullah ibn Abi Awfa reported: On the day the Messenger of Allah, peace and blessings be upon him, faced the enemy in battle, he waited until the sun had declined and then he stood in front of the people and the Prophet said:
أَيُّهَا النَّاسُ لَا تَمَنَّوْا لِقَاءَ الْعَدُوِّ وَسَلُوا اللَّهَ الْعَافِيَةَ فَإِذَا لَقِيتُمُوهُمْ فَاصْبِرُوا وَاعْلَمُوا أَنَّ الْجَنَّةَ تَحْتَ ظِلَالِ السُّيُوفِ
O people, do not desire to meet the enemy, but rather ask Allah for safety. If you meet your enemy in battle, be patient and know that Paradise is under the shade of swords.
Source: Ṣaḥīḥ al-Bukhārī 2861, Grade: Muttafaqun Alayhi
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
لاَ تَمَنَّوْا لِقَاءَ الْعَدُوِّ فَإِذَا لَقِيتُمُوهُمْ فَاصْبِرُوا
Do not wish to meet the enemy, but if you meet them, be steadfast.
Source: Ṣaḥīḥ al-Bukhārī 2863, Grade: Muttafaqun Alayhi
Muslims have been forbidden from nursing emotions of vengeance, rage, or malice in their hearts. It is not lawful for a Muslim to cultivate a desire to harm others.
Umar ibn al-Khattab, may Allah be pleased with him, said:
وَلاَ بُغْضُكَ تَلَفًا وَإِذَا أَبْغَضْتَ أَحْبَبْتَ لِصَاحِبِكَ التَّلَف
Let not your hatred be destruction, such that when you hate someone you love destruction for your companion.
Source: al-Adab al-Mufrad 1322, Grade: Sahih
Rather, Muslims have been commanded to ask Allah for security and well-being instead of war or conflict. The only intention a Muslim may have for fighting is so that the truth of Islam is protected from those who intend to exterminate it and so that the rights of justice prevail.
Abu Musa reported: A man came to the Messenger of Allah, peace and blessings be upon him, and said, “O Messenger of Allah, who is fighting in the cause of Allah? Some of us fight out of anger and others out of zeal.” The Prophet raised his head and he said:
مَنْ قَاتَلَ لِتَكُونَ كَلِمَةُ اللَّهِ هِيَ الْعُلْيَا فَهُوَ فِي سَبِيلِ اللَّهِ
He who fights to raise the word of Allah is in the way of Allah Almighty.
Source: Ṣaḥīḥ al-Bukhārī 123, Grade: Sahih
Ibn Hajar commented on this tradition, saying:
الْمُرَادُ بِكَلِمَةِ اللَّهِ دَعْوَةُ اللَّهِ إِلَى الْإِسْلَامِ وَيَحْتَمِلُ أَنْ يَكُونَ الْمُرَادُ أَنَّهُ (الجهاد) لَا يَكُونُ فِي سَبِيلِ اللَّهِ إِلَّا مَنْ كَانَ سَبَبُ قِتَالِهِ طَلَبَ إِعْلَاءِ كَلِمَةِ اللَّهِ فَقَطْ بِمَعْنَى أَنَّهُ لَوْ أَضَافَ إِلَى ذَلِكَ سَبَبًا مِنَ الْأَسْبَابِ الْمَذْكُورَةِ أَخَلَّ بِذَلِكَ
The meaning of the ‘word of Allah’ is the invitation to Islam. It is interpreted to mean that jihad would not be in the cause of Allah unless the purpose is only to raise the word of Allah, such that if anyone were to add another reason to it that would violate it.
Source: Fatḥ al-Bārī 6/28
For this reason, the companions of the Prophet did not fight for the sake of zeal, revenge, or anger. They had tranquility in their hearts even as they faced an enemy force much larger than themselves, whereas the idolaters were raging for the sake of their idols.
إِذْ جَعَلَ الَّذِينَ كَفَرُوا فِي قُلُوبِهِمُ الْحَمِيَّةَ حَمِيَّةَ الْجَاهِلِيَّةِ فَأَنزَلَ اللَّهُ سَكِينَتَهُ عَلَىٰ رَسُولِهِ وَعَلَى الْمُؤْمِنِينَ وَأَلْزَمَهُمْ كَلِمَةَ التَّقْوَىٰ وَكَانُوا أَحَقَّ بِهَا وَأَهْلَهَا وَكَانَ اللَّهُ بِكُلِّ شَيْءٍ عَلِيمًا
When those who disbelieved had put into their hearts zealotry, the zealotry of the time of ignorance, but Allah sent down His tranquility upon His Messenger and upon the believers and imposed upon them the word of righteousness, for they were more deserving and worthy of it.
Surah al-Fath 48:26
Fighting is legislated in Islam only as a last resort when it is absolutely necessary to protect people from harm and persecution.
Ali ibn Abi Talib reported: The Messenger of Allah, peace and blessings be upon him, said:
إِنَّهُ سَيَكُونُ بَعْدِي اخْتِلَافٌ أَوْ أَمْرٌ فَإِنْ اسْتَطَعْتَ أَنْ تَكُونَ السِّلْمَ فَافْعَل
Verily, after me there will be conflicts or affairs, so if you are able to end them in peace, then do so.
Source: Musnad Aḥmad 697, Grade: Sahih
Therefore, a Muslim should never want to fight the enemy. Instead, a Muslim must purify his heart from all feelings of vengeance, rage, and malice toward others, replacing these destructive diseases of the heart with the tranquility and peace that comes from worshiping Allah.
Success comes from Allah, and Allah knows best.