Neither Jewish nor Christian scriptures praise slave manumission by raising it to worship. Indeed, Islam is unique in world religions in requiring the faithful to financially help slaves win their freedom and has raised the manumission of a slave to an act of worship - if it is done to please God.
Under the caliphates, the collection and expenditure of zakat was a function of the state. In the contemporary Muslim world, it has been left up to the individual, except in some countries in which the state fulfills that role to some degree. Most Muslims in the West disperse zakat through Islamic charities, mosques, or directly giving to the poor. Money is not collected during religious services or via collection plates, but some mosques keep a drop box for those who wish it to distribute zakat on their behalf. Unlike the zakat, giving other forms of charity in private, even in secret, is considered better, in order to keep one’s intention purely for the God.
Apart from zakat, the Quran and Hadeeth (sayings and actions of the Prophet Muhammad, may the mercy and blessings of God be upon him) also stress sadaqah, or voluntary almsgiving, which is intended for the needy. The Quran emphasizes feeding the hungry, clothing the naked, helping those who are in need, and the more one helps, the more God helps the person, and the more one gives, the more God gives the person. One feels he is taking care of others and God is taking care of him.