Firstly: Defining Charity
Zakah linguistically: is purification and growth.
Zakah terminologically: is worshipping Allah, exalted, by giving a specific wajib monetary amount to legally valid recipients.
Secondary: Virtues of Charity
Charity is incredibly virtuous, and brings about great reward. Among those are: Being consistently coupled with prayer. Whenever the latter is mentioned, so is charity. It is the third of the five pillars of Islam. It is one of the signs of piety and consciousness of Allah, as well as one of the reasons of admittance into Paradise. Constantly giving charity is one of the means of reaching the status of the truthful and the martyrs. The one who willingly and contently performs it tastes the sweetness of faith.
Thirdly: The Ruling of Charity
Giving charity (zakah) is one of the fard actions of the religion and its third pillar. Consensus has been quoted over this by: Ibn Hazm, Ibn Rushd, Ibn Qudamah, and al-Nawawi.
Fourthly: The Ruling of the One Who Does Not Give Wajib Charity The one who does not give wajib charity denying its obligation
Whoever does not give charity out of denial of its obligation has disbelieved. Consensus over this has been quoted by: Ibn `Abd al-Barr, al-Nawawi, and al-Zurqani. The one who does not give wajib charity whilst ignorant of its necessity
Whoever does not give wajib charity out of ignorance of its legal obligation, like the new Muslim, does not disbelieve. They must nonetheless be made aware of its importance and necessity. This is by agreement of the four schools of jurisprudence. The one who does not give wajib charity out of miserliness
Whoever does not give wajib charity out of miserliness does not disbelieve. This is by agreement of the four schools of jurisprudence. Fifthly: The Punishment of the One Who Does Not Give Wajib Charity The one who does not pay it whilst under control of the ruler
Whoever does not pay his portion of wajib charity while under the legal jurisdiction of the ruler, then it is taken forcefully from him. Consensus has been quoted over this by: Ibn Battal, Ibn `Abd al-Barr, Ibn Qudamah, al-Nawawi, and al-San`ani. Punishing the withholder of charity by taking more than is wajib
Scholars have differed over whether the one who withholds his portion of charity should be punished by taking more of his wealth according to two views:
The first: is that only the necessary amount is taken from him. This is by agreement of the four schools of jurisprudence, as well as being the position of the majority of scholars.
The second: is that he is punished by having half his wealth  There is a difference whether it is half of all his wealth that is taken or half of the amount he withheld from charity on top of the original amount. taken from him. This is the old position of al-Shafi`i, a position among Hanbalis, and the position of al-Awza`i and Ishaq ibn Rahawayh. It is also the chosen position of Ibn al-Qayyim, Ibn `Uthaymin, and the verdict of the Permanent Committee. The one who does not pay it whilst outside control of the ruler
Those who withhold wajib charity are fought until they give it. Consensus among the Companions over this has been quoted by: Ibn Battal, Ibn `Abd al-Barr, Ibn Qudamah, and al-Nawawi.