The "five pillars" of Islam are the basis of Muslim life. Prophet Muhammad is reported to have said: 

"Islam is founded on 5 pillars; to testify that 'there is no deity except God, and Muhammad is the messenger of God;' to establish the ritual prayers; to give charity (to the needy); to perform the pilgrimage to the House (of worship in Makkah); and to fast during the month of Ramadan."

A practicing Muslim's life is centered on these pillars. The first and foremost of these is the testimony. 

"There is no deity except God; Muhammad is the messenger of God."

This simple declaration of faith is required of all those who accept Islam as their chosen way of life. The words have to be uttered with sincere conviction and under no coercion. The significance of this testimony is the belief that the only purpose of life is to serve and obey God; and this is achieved through following the example of Prophet Muhammad. 

Muslims believe that throughout history, God sent His chosen messengers to guide humankind. The testimony that these prophets taught was similar. The first commandment found in the Bible is "I am the Lord, thy God; thou shalt not have other gods before Me." This belief in the Oneness of God is central to Islam and permeates all of Muslim life.