A person did not pay zakat for four years; what is incumbent upon him?
Answers: As all Muslims should know, zakat is a duty that will not end until it is executed. The delay in paying zakat mostly either because of the loss of wealth or maybe because of own ignorance.
This person has sinned by delaying the payment of his zakat because it is incumbent upon a person to pay zakat as soon as it becomes obligatory, and not to delay it, because the basic principle regarding obligations is that they are fulfilled immediately.
There is also no disagreement among scholars that the person must settle the payment of zakat that is delayed for every expiration year whether is one or four haul (year). Anyone who has accumulated-delay in his wealth of four zakat payment while his condition is still alive must then be paid off all zakat by yearly at the required rate (depends on the type of wealth; if its zakat on money then the rate is 2.5%).
According to Shaikh Mohammad bin Salih Al-‘Uthaimeen in Fatawa Arkanul Islam; this person should repent to Allah, the Almighty, the All-Powerful for this act of disobedience and he must pay the zakat for all the previous years, and nothing is omitted from that zakat; rather he must repent and pay it quickly, so that he does not increase his sin by delaying further.