In Surah Nisaa, Allah says:
Translation: O ye who believe! Take your precautions, and either go forth in parties or go forth all together (Surah Nisaa, 4:71).1
The message: prepare, and fight in groups.
A related incident: after the battle of Uhud, many tribes targeted the Muslims to take them down once and for all. The day the Prophet (صلي الله عليه وسلم) returned from battle, he slept, prayed ‘Isha (alone), and the next day, after Fajr, said “we’re going after [the fleeing army].” And who did he take with him? Only those who fought the day before.
The Qur’an attends to all aspects of life–including battle tactics.
Also, tactics mentioned in the Qur’an, in context of battle techniques, also apply to ideological battles. And as with (physical) wars, with ideological wars, one must prepare and fight.
Wallahu ‘alim.
(1) Pickthall, Muhammad M., trans. Al-Qur’an Al-Kareem: Parallel Arabic text with English Translation. One Ummah Network.12 Feb. 2006 <http://www.oneummah.net/quran/quran.html>.