1 – Zakaah is enjoined in Islam on specific things, which are: gold, silver, crops, fruits, trade goods and an’aam livestock, i.e., camels, cattle and sheep.
2 – Zakaah is subject to the conditions that one full Hijri have passed since acquiring the wealth, and that the wealth meet the minimum threshold (nisaab), and it is a specific portion of wealth.
3 – Allaah has enjoined that zakaah be given to certain types of people, and it is not permissible to give it to anyone else. They are the people mentioned in the verse (interpretation of the meaning):
“As-Sadaqaat (here it means Zakaah) are only for the Fuqaraa’ (poor), and Al‑Masaakeen (the poor) and those employed to collect (the funds); and to attract the hearts of those who have been inclined (towards Islam); and to free the captives; and for those in debt; and for Allaah’s Cause (i.e. for Mujaahidoon — those fighting in a holy battle), and for the wayfarer (a traveller who is cut off from everything); a duty imposed by Allaah. And Allaah is All-Knower, All-Wise”
[al-Tawbah 9:60]
4 – Whoever dies and owes zakaah, his heirs must pay it from his wealth, and that takes precedence over the will (wasiyah) and inheritance.
5 – The one who withholds zakaah is to be punished, as it says in the hadeeth narrated by Muslim in his Saheeh (987) from Abu Hurayrah (may Allaah be pleased with him) who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “There is no owner of treasure who does not pay his zakaah, but it will be heated in the Fire of Hell and made into plates with which his sides and forehead will be branded until Allaah passes judgement between His slaves on a Day the length of which will be like fifty thousand years, then he see shown his path and whether it leads to Paradise or to Hell. And there is no owner of camels who does not pay zakaah on them, but a soft sandy plain will be prepared for him and they will be made to step on him. Every time the last of them has gone the first of them will return, until Allaah passes judgement between His slaves on a Day the length of which will be like fifty thousand years, then he will see his path and whether it leads to Paradise or to Hell. And there is no owner of sheep who does not pay zakaah on them but a soft sandy plain will be prepared for him, and he will find none of them missing, with twisted horns or without horns or with broken horns, and they will be made to gore him with their horns and trample him with their hooves. Every time the last of them has gone the first of them will return, until Allaah passes judgement between His slaves on a Day the length of which will be like fifty thousand years, then he will see his path and whether it leads to Paradise or to Hell…”
6 – According to the four schools of law, it is not permissible to give zakaah to one’s ascendants or descendents. Ascendants include one’s mother, father, grandfathers and grandmothers; descendents include one's children and their children.
7 – It is not permissible to give zakaah to one who is rich or who is strong and able to earn a living.
It was narrated that ‘Ubayd-Allaah ibn ‘Adiyy said: Two men told me that they came to the Prophet (peace and blessings of Allaah be upon him) during the Farewell Pilgrimage when he was distributing the zakaah and asked him for some of it. He looked them up and down, and saw that they were strong and able-bodied. He said, “If you wish, I will give you some, but those who are rich or strong and able to earn have no share of it.”
Narrated by Abu Dawood, 1633; al-Nasaa’i, 2598; classed as saheeh by Imam Ahmad and others
8 – In the case of zakaah, it is better for it to be taken from the rich of a land and given to their poor.
9 – It is not permissible to give zakaah to kuffaar and mushrikeen.
10 – It is not permissible for a Muslim to give zakaah to his wife. Ibn al-Mundhir narrated that there was scholarly consensus on this point.