Bay'ah (Arabic: بَيْعَة, literally to sell), in Islamic terminology, is an oath of allegiance to a leader. It is known to have been practiced by the Islamic prophet Muhammad. Bay'ah is sometimes taken under a written pact given on behalf of the subjects by leading members of the tribe with the understanding that as long as the leader abides by certain requirements towards his people, they are to maintain their allegiance to him. Bay'ah is still practiced in countries such as Saudi Arabia and Sudan. In Morocco, Bay'ah is one of the foundations of the Monarchy. In many Islamic traditions, the meaning of bay'ah is to sell ones self to a spiritual master, pir or sheikh in exchange for the spiritual knowledge which he gives.

The tradition of bay'ah can be traced back to the era of Muhammad. From the beginning bay'ah was taken by Muhammad as an oath of allegiance. Anybody who wanted to enter Islam did so by reciting the basic statement of the faith expressing his faith in the oneness of God and the prophethood of Muhammad. In addition to this the prophet formally took bay'ah from the people and tribes. Through this formal act they entered the Islamic community and showed their willingness to follow and obey Muhammad. The wordings of the oath differ in different traditions but it contains the shahada and prayers of repentance.

A bay is a large body of water connected to an ocean or sea formed by an inlet of land due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight. A cove is a circular or oval coastal inlet with a narrow entrance; some coves may be referred to as bays.

Bays were significant in the history of human settlement because they can provide a safe place for fishing. Later they were important in the development of sea trade as the safe anchorage they provide encouraged their selection as ports. Any bay may contain fish and other sea creatures or be adjacent to other bays. For example, James Bay is adjacent to Hudson Bay. Large bays, such as the Bay of Bengal and the Hudson Bay, have varied marine geology.

There are various ways that bays can be created. The largest bays have developed as a result of continental drift. As the super-continent Gondwana broke up along curved and indented fault lines, the continents moved apart and the world's largest bays formed. These include the Gulf of Guinea, Persian Gulf, Gulf of Alaska, Gulf of Mexico and the Bay of Bengal which is the largest bay in the world.

Abu Bakr (Abdullah ibn Abi Quhafa) (Arabic: عبد الله بن أبي قحافة, Transliteration: ʿAbd Allāh ibn Abī Quḥāfah, c. 573 CE - 634 CE) also known as Abū Bakr as-Șiddīq (Arabic: أبو بكر الصديق) was a senior companion (Sahabi) and the father-in-law of the Islamic prophet Muhammad. He ruled over the Rashidun Caliphate from 632–634 CE when he became the first Muslim Caliph following Muhammad's death. As Caliph, Abu Bakr succeeded to the political and administrative functions previously exercised by Muhammad, since the religious function and authority of prophethood ended with Muhammad's death according to Islam. He was called Al-Siddiq (The Truthful) and was known by that title among later generations of Muslims.

As a young man, Abu Bakr became a cloth merchant and he traveled extensively in Arabia and neighboring lands in the Middle East, through which he gained both wealth and experience. He eventually came to be recognized as the chief of his clan. On his return from a business trip to Yemen, he was informed that in his absence Muhammad had openly declared his prophethood. Not long after, Abu Bakr accepted Islam and was the first person outside the family of Muhammad to openly become a Muslim. He was instrumental in the conversion of many people to the Islamic faith and early in 623, Abu Bakr's daughter Aisha was married to Muhammad, strengthening the ties between the two men.