Consequences in the Hereafter

"And those who hoard gold and silver and do not spend it in the way of Allah, give them tidings of a painful punishment. On that day it (i.e. the wealth) will be heated in the fire of Jahannam, then their foreheads and their flanks and their backs will be branded therewith and (it will be said to them): Here is (the treasure) which you hoarded for yourselves. Now taste that which you had been hoarding." (9:34-35)

Note: Majority of the Sahaabah and ulamaa are agreed that the severe punishment mentioned in this verse is for those who do not pay Zakaat. May Allah protect us from such severe punishments.

"And let not those who hoard up wealth which Allah has bestowed upon them of His bounty think that it is better for them. No, it is worse for them. That which they hoard will be made a collar (in the form of a snake and put around their necks) on the Day of Qiyaamah." (3:180)

Note: Imaam Raazi writes in his tafseer, 'This verse does not apply to the cases of Nafl (optional) spending. It applies to cases of failure in obligatory spending.'

This is substantiated by a Hadeeth in Bukhaari that Rasoolullah Sallallahu alayhi wasallam said,
"The person on whom Allah bestowed wealth, and he does not give Zakaat on it, then on the Day of Judgement, his wealth will be transformed for him into a large bald snake with two black spots over it's eyes; it will wind round his neck on the Day of Qiyaamah then grab both his jaws and say: 'I am your wealth, I am your treasure."' Then Rasoolullah Sallallahu alayhi wasallam  recited the above verse.

Aboo Hurayrah radhiyallahu anhu reports that Rasoolullah Sallallahu alayhi wasallam said,
"If anyone possessing gold and silver does not pay what is due, then on the Day of Qiyaamah, his gold and silver will be made into sheets and will be heated in the fire of Jahannam. His side, forehead and back will then be branded with (the heated sheets), again and again, on that day, the duration of which will be fifty thousand years."

Bukhaari, Muslim

Once Rasoolullah Sallallahu alayhi wasallam  saw gold bangles on the hands of two women. He inquired if they gave Zakaat for the bangles? They replied, "No." Rasoolullah Sallallahu alayhi wasallam  said, "Do you wish that on the Day of Qiyaamah you be made to put on bangles of fire?" They replied, "No." He said, "Give Zakaat on them."

Tirmizi

The following facts are clear from the aforementioned discussion: