In Ayahs 99 and 100 of Surah Al-Mu’minoon, Allah (SWT) said:

“When death comes to one of them, he cries; O’ my God, let me return, so as to make amends for the things I neglected. Never! This will not go beyond his words; a barrier stands behind such people until the very Day they are resurrected.”

In the above Ayahs, the dead ones express their regrets and requests to return to the world. Avoiding Zakat will cause regret at the time of death and these people want to return to the world; but no answer except “never” will be given to them by Allah (SWT). Regarding the above Ayahs, it is narrated from Imam Sadeq (AS) who said: The mentioned Ayahs are about the one who avoids paying Zakat [1].

[1] Majma’ul Bayan, Vol. 7-8, Page 187.

Source: en.shafaqna.com