It is narrated from Hazrat Muawiyah (may Allah be pleased with him) that I heard the Prophet (peace and blessings be upon him) say: For every forty freely-grazing camels, one bint labun is obligatory, and according to this calculation of zakat, no camel should be separated. Whoever pays zakat himself with the intention of reward will receive its reward, and whoever does not pay zakat, we can take it from him by force. The share of his camel is the decision of our Lord, and nothing from it is lawful for the family of Muhammad (peace and blessings be upon him).