Take your precautions (Surah An-Nisa' 4: 71)

The Necessity of Taking Necessary Precautions Against the Enemy

Allah commands His faithful servants to take precautions against their enemies, by being prepared with the necessary weapons and supplies, and increasing the number of troops fighting in His cause.

in parties  means, group after group, party after party, and expedition after expedition. `Ali bin Talhah reported that Ibn `Abbas (Radhi Allahu Anhu) said that,

and either go forth in parties means, "In groups, expedition after expedition,

or go forth all together,  means, all of you.'' Similar was reported from Mujahid, `Ikrimah, As-Suddi, Qatadah, Ad-Dahhak, `Ata' Al-Khurrasani, Muqatil bin Hayyan and Khusayf Al-Jazari.

Source: Tafsir ibn Kathir (Abridged)