Upon encountering an enemy or those in authority

Allāhumma innā naj`aluka fī nuḥūrihim wa na`ūdhu bika min shurūrihim.

O Allah, we ask You to restrain them by their necks, and we seek refuge in You from their evil.

[ Abu Dawud 2/89, and Al-Hakim graded it authentic and Ath-Thahabi agreed 2/142. Hisn al-Muslim 126 ]

Allāhumma anta `aḍudī, wa anta naṣīrī, bika ajūlu, wa bika aṣūlu, wa bika uqātil.

O Allah, You are my strength and You are my support. For Your sake, I go forth and for Your sake, I advance and for Your sake, I fight.

[ Abu Dawud 3/42, At-Tirmidhi 5/572. See also Al-Albani, Sahih At-Tirmidhi 3/183. Hisn al-Muslim 127 ]

Ḥasbunallāhu wa ni`mal-wakīl.

Allah is sufficient for us and the best of those on whom to depend.

[ Al-Bukhari, 5/172. Hisn al-Muslim 128 ]