To the commander of a vanguard contingent dispatched to Syria
Nahj al-Balāgha|Volume 1|Book 2|Chapter 11
وَاعْلَمُوا أَنَّ مُقَدِّمَةَ الْقَومِ عُيُونُهُمْ، وَعُيُونَ الْمُقَدِّمَةِ طَلاَئِعُهُمْ. وَإِيَّاكُمْ وَالتَّفَرُّقَ، فَإِذَا نَزَلْتُمْ فَانْزِلُوا جَمِيعاً، وَإذا ارْتحَلْتُمْ فَارْتَحِلُوا جَمِيعاً، وَإِذَا غشِيكُمُ اللَّيْلُ فَاجْعَلُوا الرِّمَاحَ كِفَّةً، وَلَا تَذُوقُوا النَّوْمَ إِلَّا غِرَاراً أَوْ مَضْمَضَةً.
And know that the vanguard of an army serves as their eyes, and the eyes of the vanguard are their informers. Beware of dispersal. When you halt do so together and when you move you should move together. When night comes fix your spears in a circle and do not sleep except for dozing or napping.