What is the ruling on one who pays an incomplete zakat on his wealth, and what is the difference between him and one who does not pay it at all?

It is forbidden to diminish Zakat, and it is a form of defrauding (tatfif) for which Allah has threatened woe upon its perpetrator. One who pays deficient Zakat is not like one who does not pay it at all, for the latter's sin is greater, and Allah has threatened him with severe punishment. The Hadith contains a severe warning against those who refrain from paying it. If there is a Muslim ruler, he must take Zakat by force, and if those who refuse are a group with power, he should fight them until they pay it.