
The word 'zakat' means "purity" and "growth" in the dictionary. In Shariah terms zakat is the giving a specific juz of a special property to the specific person as prescribed by Sharia for the sake of Allah. Zakat is fard by the Quranic verses and the Sunnah of the Messenger of Allah.
Muslims have agreed on the obligation of zakat in all ages and places, that is to say, "Zakat is fard worship". The Companions fought against those who forbade giving zakat. Whoever denies the fard of zakat becomes a disbeliever. He is called to repentance three times. If he does not repent, he will be put to death as an apostate.
Someone who denies the obligation of zakat due to his newfound in Islam or his uneducated growth abroad will be explained, taught and not immediately judged as a disbeliever. Those who do not perform the Zakat, suffering is punished in this world and the next.