211. Imām Ali (a.s.) – from his instructions that he used to write to whomever he appointed for the collection of taxes: “Move on with the fear of God who is One and has no partner. Do not frighten any Muslim. Do not pass over his lands without his consent. Do not take from him more than God’s right in his wealth. When you go to a tribe, you should stay at their watering place instead of entering their houses. Then go to them maintaining your dignity, calm. When you are in their midst salute them and do not be negligent in greeting and respecting them.
Tell them: “O servants of God, the vicegerent of God and His caliph has sent me to you to collect from you God’s right in your wealth. Is there anything of His right in your wealth? If so, give it to His vicegerent.” If someone says no, then do not repeat the demand [accept his plea]. If someone speaks to you in the affirmative, then go with him without frightening him, threatening him, making him nervous or behaving with tyranny. Take what he gives you such as gold or silver (coins). If he has cattle or camels do not enter upon them save with his permission, because the major part is his. Therefore, when you get there do not enter upon them as one who has full control over them or in a violent manner.
Do not scare away and frighten any animal; do not tease and bother their owner. Divide the property into two parts and let the owner choose one. When he has chosen do not object to it. Then divide the remaining into two parts and let him choose one and when he has chosen do not raise any objection. Continue like this till only that much remains which is enough to satisfy God’s dues, then take God’s due from it. If he still disputes your action allow his views, then mix the two (separated) parts and repeat what you had done before until you take God’s due from his wealth.
Do not take an old, decrepit, broken, limbed, sick or unsound animal. Do not entrust them (for custody) except to one whom you are confident of his faith and takes care of Muslims' wealth until he hands it over to their chief to distribute it. Do not entrust the animal to anyone except a well wisher, God-fearing, trustworthy and watchful, and a person who is not harsh on Muslims’ wealth nor makes them exhausted too much, nor tires them, nor labors them. Then send to us all that you have collected and we shall deal with it as God has ordered.
When your trustee takes over (the animal) tell him that he should not separate the she-camel from its young and not to milk so much that nothing is left for its young and also that he should not exhaust it in riding, and should treat it and all rest fairly. He should allow camels (that are tired) to rest, and drive with ease those whose hoofs have been rubbed off. When passing a water spring he should take the camels there for drinking and should not take them away from vegetated land to barren paths. He should allow them rest now and then and give them time near water and grass. In this way when they reach us by will of God they will be fat with plenty of marrow and would not be fatigued or distressed. We will then distribute them according to the (commands of) the Book of God and the sunna of His Prophet (s.a.w.). Certainly this will be a great source of reward for you and a means to secure your salvation by the will of God.”1
1.. Nahj al-Balāghah, Letter ۲۵, al-Kāfi, vol. ۳, p. ۵۳۶, h. ۱, Tahdhib al-Ahkām, vol. ۴, p. ۹۶, h. ۲۷۴.