Conversion to Islam is accepting Islam as a religion or faith and rejecting any other religion or irreligion. Requirements Converting to Islam requires one to declare the shahādah, the Muslim profession of faith ("there is no god but Allah; Muhammad is the messenger of Allah"). In the Islamic religion, it is believed that everyone is Muslim at birth. In Islam, circumcision is considered a sunnah custom and is never mentioned in the Quran but in hadith or sunnah. The majority of clerical opinions holds that circumcision is not required upon entering the Muslim faith. Islamic missionary activities Dawah (, ) is the act of inviting or calling people to embrace Islam. In Islamic theology, the purpose of da‘wah is to invite people, Muslims and non-Muslims, to understand the worship of God as expressed in the Qur'an and the sunnah of Muhammad and to inform them about Muhammad. Da'wah as the "Call towards God" is the means by which Muhammad began spreading the message of the Qur'an to mankind. After Muhammad, his followers and the Ummah (Muslim community) assumed responsibility for it. They convey the message of the Qur'an by providing information on why and how the Qur'an preaches monotheism. Muhammad saw Islam as the true religion and mission of all earlier prophets. He believed that their call had been limited to their own people but that his was universal. His mission as the final prophet was to repeat to the whole world this call and invitation (dawa) to Islam. Muhammad wrote to various non-Muslim rulers, inviting them to convert. Conversion rate Counting the number of converts to a religion is difficult, because some national censuses ask people about their religion, but they do not ask if they have converted to their present faith, and, in some countries, legal and social consequences make conversion difficult, such as the death sentence for leaving Islam in some Muslim countries. Statistical data on conversion to and from Islam are scarce. According to a study published in 2011 by Pew Research, what little information is available suggests that religious conversion has no net impact on the global Muslim population as the number of people who convert to Islam is roughly similar to those who leave Islam. According to another study published on 2015 by Pew research center, Islam is expected to experience a modest gain of 3 million adherents through religious conversion between 2010 and