Al-Madinah was secure from three sides because of the walls of the houses...

Al-Madinah was secure from three sides because of the walls of the houses, hills and the oasis. Only the Eastern end of the city was not secure and always the entry point for any invaders. The Prophet (a.s) shifted all the women and children to small fortresses within al-Madinah and the men all came out with crowbars to dig the trench.

They surveyed the area, fixed the benchmarks, divided the entire length into blocks of the length of forty hands each, and entrusted each block to a group of ten persons. The Prophet (a.s) took active part in the work and assured the Muslims that one day they would rule Syria, Rome, Pars and Yemen! Arabs were not aware of the construction of the trenches. This was first thought of by the grand son of Faridūn, Manocher, who invented the trenching for defensive purposes.

For the first time in Arabia, Salman was introducing it. He was not only supervising the work of others but was giving a helping hand to groups along the length of the trench. Because of his dexterity, both Muhajirūn and the Ansar wanted Salman to be with them. Therefore, the Muhajirūn said, “Salman is ours!” The Ansar too echoed, “Salman is one of us!” The Prophet, when he heard this, said: “Salman is ours!

Salman is from our !”[1] Therefore the Muslims, who were three thousand in numbers, worked day and night and dug a five yards wide, five yards deep and three and half miles long trench. The Prophet (a.s) got erected eight defensive stations along the length of the trench, and at each station was posted a Muhajir and an al-Ansari to keep constant vigil along with some men to help in time of need. They had stocks of stones to keep as missiles to prevent the enemy men from crossing over the trench.

When the Jews and the infidels reached the environs of al-Madinah, they found that the huge trench was a big hurdle in their way! They said: By God! No Arab has devised this strategy so far![2] The Jews and the Quraysh were of the view that because of their numerical and material strength, they would take on the Muslims as soon as they reached al-Madinah and immediately bring them down to their knees! But this new defensive strategy had pulled back their advancing steps.

They had a feeling of dejection on confronting the hurdle. [1] Tārīkh al-Kāmil, Vol 2, Page 122 [2] Sīrat Ibn Hushām, Vol 3, Page 235 One of the Jewish tribes with whom the Prophet (a.s) had the agreement of peace was Banū-Qurayzah.