The Seventy-Seven Branches of Faith [Mukhtasar]
God Most High said: They were enjoined only to worship God, sincere in their faith in Him alone - and of upright religion - and to establish the Salat and the Zakat. Such is the upright religion, [98:5] and: Those who lay up treasures of gold and silver and spend them not in the way of God; give them the news of a painful punishment, on the Day when that [wealth] will be heated in hellfire, and their foreheads and their sides and their backs branded therewith: "This is the treasure which you laid up for yourselves! Taste, then, your hoarded treasure!" [9:34-35] and: Let not those who are miserly with what God has given them of His bounty think that this is good for them. Rather, it is bad for them. That which they withhold shall be hung around their necks on the Day of Arising. [3:180]
Bukhari and Muslim relate on the authority of Ibn `Abbas (radiyallahu `anhu) that the Messenger of God (sallallahu `alayhi wa sallam) sent Mu`adh to the Yemen he told him, "You are going to a people who have a Scripture, so call them to testify that there is no deity but God, and that I am the Messenger of God. If they respond to this, then teach them that God has imposed five Salats upon them in every day. If they respond to this, then teach them that God has imposed upon them a charity to be taken from the wealthy amongst them and given to their poor. If they respond to this, then beware of taking any more of their wealth! Beware also of the prayer of the oppressed, for there is no veil between such a prayer and God."
Bukhari relates on the authority of Abu Hurayra that the Prophet (sallallahu `alayhi wa sallam) said, "Whoever is given wealth by God and does not pay the Zakat due thereupon shall find that on the Day of Arising it is made to appear to him as a hairless snake with two black specks, which chains him, and then seizes him by his jaw and says, 'I am your wealth! I am your treasure!'" Then he recited the verse, 'Let not those who are miserly with what God has given them of His bounty think that this is good for them. Rather, it is bad for them. That which they withhold shall be hung around their necks on the Day of Arising.' [3:180]