Nahj al-Balāgha

Hadith 1469
governance
ومن عهد له (عليه السلام) كتبه للأشتر النخعي لما ولاه على مصر وأعمالها حين اضطرب أمر أميرها محمد بن أبي بكر، وهو أطول عهد كتبه وأجمع للمحاسن
Instructions [1] written for (Mālik) al-Ashtar an-Nakha‘ī, when the position of Muḥammad ibn Abī Bakr had become precarious, and Amīr al-mu’minīn had appointed al-Ashtar as the Governor of Egypt and the surrounding areas; it is the longest document and contains the greatest number of beautiful sayings.
Source: al-Sharīf al-Raḍī