The Rules of War in Islam

Lessons from the Rightly Guided Khulafa’

“You are not fighting men; you are fighting your fate.”

an unknown Arab to the general of the Persian army before his defeat at Qadisiyyah

For the past few years, I have made a point of studying history, especially Islamic history. And sometimes one of the best ways to learn something is to teach it, which is why I volunteered to do just that this year. And so far that decision has paid off immensely as my own knowledge of the subject has bloomed in beautiful and unexpected ways, most recently regarding the era of the Rightly Guided Khulafa’. This period is the first 30 years after the death of the Prophet Muhammad ﷺ during which the Muslims were ruled by the most eminent and illustrious of his Companions. I was blessed to receive a book on the subject which I’ve thoroughly enjoyed, and now I just want to share some highlights and reflections based on my reading so far. The book is called The History of the Four Caliphs (Itmam al-Wafa’ fi Sirat al-Khulafa’) by Shaykh Muhammad Al-Khudari Bak Al-Bajuri.

Before the Prophet Muhammad ﷺ died, he had prepared an army to engage the Byzantines again after a previous expedition in which three leaders of the army had fallen in battle, first among them Zayd ibn Harithah, who was the adopted son of the Prophet Muhammad ﷺ. When dispatching the army to return to the Byzantines, the Prophet ﷺ selected Zayd’s son Usamah to be the leader even though he was only 19 or 20 years old at the time. After the death of Prophet Muhammad, ﷺ when Abu Bakr became the Khalifah, some senior companions suggested changing the appointment. But he absolutely refused to change what had been a command from the Messenger ﷺ; so the army did eventually depart with Usamah bin Zayd in charge. But because he was young and this might have been his first time leading the army, Abu Bakr gave him some advice, teaching what he had undoubtedly learned from from the Prophet. ﷺ

Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman, nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy's flock, save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone.

This is a basis for the rules of war in Islam and is taken quite seriously. In fact it might be the earliest ever prohibition of killing non-combatants in warfare, explicitly identifying protected classes, namely children, women, elders, and monks.

“Surely God does not wipe out evil with evil; rather He wipes out evil with good.”

‘Umar ibn al-Khattab to Sa’d ibn Abi Waqqas

As I’m writing, December 2023, Israel has resumed a horrific bombing campaign that is targeting homes, schools, mosques, churches, and hospitals, deliberately killing children, women, journalists, and doctors. Meanwhile, some enemies of Islam and propagandists have started trying to smear Islam as some radically violent ideology. But anyone who actually looks can see that Islam prohibits killing civilians, while the cruel occupation force that fancies itself “the most moral army” kills even babies without regard or remorse.

And in the midst of frustration, watching war crimes committed daily with abandon, there is also encouraging advice from the second khalifah, ‘Umar ibn al-Khattab. This is what he wrote to Sa’d ibn Abi Waqqas, who had been sent as the leader of an army to Iraq where he conquered the Sassanid empire.

I command you and those with you to be more wary of your own selves than of your enemy; truly the sins of an army are more frightening to them than the enemy. The Muslims are assisted by their enemy’s disobedience to God. Were it not for that, we would not have the strength to fight them. Our numbers are not equivalent to theirs, nor are our resources. If we equal them in disobedience to God, they will be stronger than us. If not, we will be helped through our virtue and not through our strength.

Do not commit any acts of disobedience while you are fighting for the cause of God. Do not say: “Our enemy is worse than us and he will therefore not have the upper hand over us.” There were times when nations who were worse were given authority over those who were better.

These men conquered the Persian empire, defeated the Byzantines in Syria, Palestine and Egypt—essentially fighting the superpowers of their day, though they were a nation that hadn’t even been united a decade before. They had neither superior numbers, nor superior technology, yet in just 30 years Islam had spread from a single city in Arabia to beyond Tripoli in the west and Kabul in the east, lands which haven’t left Islam in 1400 years. So I just love these reminders that the real objective in our lives and our struggle is righteousness, because ultimately victory is only from God Almighty.