SHAFAQNA – In Ayahs 34-35 of Surah At-Tawbah, Allah (SWT) said: “Believers, many rabbis and monks wrongfully consume people’s possessions and turn people away from God’s path. [Prophet] tell those who hoard gold and silver instead of giving in God’s cause that they will have a grievious punishment; on the Day it is heated up in hell’s fire and used to brand their foreheads, sides, and backs, they will be told: This is what you hoarded up for yourselves! Now feel the pain of what you hoarded.”
One of the causes of painful punishments in hell fire is avoiding Zakat. That is why Allah (SWT) warns all those who claim to be scholars of the religion but love the worldly possessions to avoid hoarding and gathering wealth and pay Zakat; otherwise they will be trapped in hell fire on the Day of Judgement. Avoiding payment of Zakat on purpose by believers is considered as a great sin and as a result, eternal punishment will be inflicted on them in the hell fire. In this regard, it is narrated from Imam Sadeq (AS) who referred to the above Ayahs and considered avoiding Zakat as one of the great sins 
 Tafseer Nooru-Thaqalayn, Vol. 2, Page 214, Hadith 135.