It is narrated from Imam Malik, may Allah have mercy on him, that Sayyiduna Abu Bakr Siddiq, may Allah be pleased with him, said: If they withhold even a rope used for tying a camel, I will fight against them for it.

It is narrated from Sayyiduna Zaid bin Aslam (may Allah be pleased with him) that Sayyiduna Umar bin Khattab (may Allah be pleased with him) drank some milk and found it pleasant. He asked, "Where did this milk come from?" The one who had brought it replied, "I went to a watering place," and he mentioned its name, "where the animals of zakat were drinking water. The people there milked them and gave it to me. I put it in my water-skin, and this is the same milk that you drank." So Sayyiduna Umar (may Allah be pleased with him) put his hand in his mouth and vomited.

Imam Malik, may Allah have mercy on him, said: In our view, the ruling is that whoever withholds that which Allah has ordained and does not allow the Muslims to take it, then it is obligatory upon the Muslims to fight against that person until they take that right.

It reached Imam Malik, may Allah have mercy on him, that a governor wrote to Hazrat Umar bin Abdul Aziz, may Allah have mercy on him, that a man does not give the zakat of his wealth. Hazrat Umar, may Allah have mercy on him, wrote in reply: Leave him and do not take zakat from him along with the Muslims. When this news reached that man, he felt bad and paid the zakat of his wealth. After that, the governor informed Hazrat Umar, may Allah have mercy on him, and he wrote in reply: Take the zakat from that man.