Salman’s Idea — The Trench Strategy
Salman al-Farisi, a Persian companion who had converted to Islam, suggested the trench (khandaq) — a defensive innovation from Persian warfare unknown to the Arabs. The Prophet immediately adopted it.
The trench was dug on the northern approach to Medina (the south was protected by lava fields, the east and west by dense date palms and buildings). The approximately 2.5-mile trench, reportedly 4-5 meters wide and 3 meters deep, took the Muslim community about 2-3 weeks to dig — the entire community participated, including the Prophet (SAW), who dug and carried earth alongside everyone else.
The miracle of the rock: During digging, workers struck a rock they could not break. The Prophet struck it three times with a pickaxe. On each strike he reportedly saw visions: the keys of Yemen, the keys of Syria and Byzantium, the keys of Persia. The companions said the Prophet was predicting future conquests — a prophecy that materialized within decades.
The Siege — 27 Days of Standoff
The 10,000-man Confederate army arrived to find a trench they could not cross with conventional cavalry. Their attempted crossings were repelled by arrows. The standoff settled into an exhausting siege.
The critical event — Banu Qurayza: The Jewish tribe of Banu Qurayza, under their treaty with the Muslims, was expected to defend Medina from within. During the siege, they were approached by the Banu al-Nadir (who had been expelled from Medina earlier) to join the Confederates. They eventually broke the treaty, creating a threat from within Medina that dramatically worsened the Muslim position.
Ali ibn Abi Talib’s single combat: When a group of Meccan warriors led by Amr ibn Abd Wudd managed to cross a narrow point in the trench, Ali ibn Abi Talib killed Amr — arguably the greatest warrior among the Quraysh — in single combat. The Prophet described it: “Ali’s strike on the day of Khandaq is greater in merit than the worship of both jinn and mankind.”
The Withdrawal — Divine Wind and Confederate Disintegration
After 27 days, Allah sent a severe winter wind (rih) that destroyed the Confederates’ tents, overturned their cooking pots, extinguished their fires, and made camp life impossible. Combined with the trench’s impregnability and the failure to secure Banu Qurayza’s full cooperation, Abu Sufyan led the withdrawal.
The Confederates’ departure marked the effective end of offensive Meccan power. The Quran: “And Allah repelled those who disbelieved, in their rage, not having obtained any good. And sufficient was Allah for the believers in battle, and ever is Allah Powerful and Exalted in Might.” (33:25)
The Aftermath — Banu Qurayza
After the battle, the Muslims turned to the breach of treaty by Banu Qurayza. After a siege, Banu Qurayza surrendered and requested that their fate be decided by their former ally Sa’d ibn Mu’adh. Sa’d — who was dying from a wound received at Khandaq — ruled that the treaty-breaking fighting men be executed and the women and children taken as captives. The Prophet accepted the ruling: “You have ruled by the judgment of Allah from above seven heavens.” This remains one of the most debated events in seerah scholarship.
See also: Prophet Muhammad, Seerah Medina, Seerah Badr, Seerah Uhud, Ali Ibn Abi Talib, Sahaba, Fitna