Muslims believe that there is only one God, called Allah in Arabic. Muslims also believe that Islam existed long before Muhammad though it was not called Islam until the revelation of Surah al-Ma'ida. Muslims believe that this religion had evolved with time from the time of Adam until the time of Muhammad and was completed with the revelation of verse 3 of Surah al-Ma'ida:
This day have I perfected your religion for you, completed My favour upon you, and have chosen for you Islam as your religion.
The Qur'an describes many Biblical prophets and messengers as Muslim: Adam, Noah (Arabic: Nuh), Moses and Jesus and his apostles. The Qur'an states that these men were Muslims because they submitted to God, preached his message and upheld his values. Thus, in Surah 3:52 of the Qur'an, Jesus’ disciples tell Jesus, "We believe in God; and you be our witness that we submit and obey (wa ashahadu bil-muslimūna)."Muslims consider making ritual prayer five times a day a religious duty (fard) (see the section on Ismāˤīlīs below for exceptions); these five prayers are known as fajr, dhuhr, ˤasr, maghrib and ˤishā'. There is also a special Friday prayer called jumuˤah. Currently, the most up to date reports from an American think-tank and PBS have estimated 1.2 to 1.57 billion Muslims populate the world, or about 20% of an estimated 2009 world population of 6.8 billion, with 60% in Asia and 20% of Muslims living in the Middle East and North Africa.