In Islamic law (sharia), marriage (nikāḥ نکاح) is a legal and social contract between two individuals. Marriage is an act of Islam and is strongly recommended. Polygyny is permitted in Islam under some conditions, but polyandry is forbidden. Marriage in Islam The Nikāḥ (Arabic: نكاح, literally, "to collect and bind together") is the first—and most common—form of marriage for Muslims. It is described in the Qur'an in Surah 4:4. Regulations: While intended to be a permanent state, it can be terminated by the husband engaging in the Talaq process or the wife seeking a Khula. The couple inherit from each other. A legal contract is signed when entering the marriage. However it is not a requirement that the contract be in writing. It may be oral, especially amongst illiterates; and if an agreed end-date is specified in the nikāḥ contract: In Sunni jurisprudence, the contract is invalid. In Shia jurisprudence, the contract defines a temporary marriage, nikāḥ mut'ah. Requirement of witnesses: two witnesses from both sides Permission from Wali: Sunni: Compulsory (Maliki, Shafi'i, Hanbali) or Strongly recommended (Hanafi) Shia: Depending on the scholar, it is either obligatory or obligatory based on precaution. Nikah Halala Nikah halala is also known as tahleel marriage and is a practice in which a woman, after being divorced by a final divorce, marries another man, consummates the marriage, and divorces immediately for the sole purpose of remarrying her former husband. It is prohibited in Islamic law. Nikah Ijtimah Nikah ijtimaa, or combined marriage, is a form of marriage practiced in pre-Islamic Arabia, in which multiple men would have intercourse with a woman, and if she bore a child, she would choose one of the men to be the father of the child. This form of marriage was outlawed by Islam, which requires that any man and woman be married prior to sexual intercourse. Nikah Istibdaa is a marriage ( نکاح استبضاع) in which a husband would send his wife to another person, usually of noble lineage, to have sexual relations with him.