The basic requirement to become a Muslim is to declare, “Ashhadu an laa ilaaha illa Allah, wa ashhadu anna Muhammadan rasul Allah.” In English this means, “I testify that there is no god but Allah, and that Muhammad is the Messenger of God.”
Anyone who proclaims this phrase joins the ranks of the Muslim nation (ummah). This statement marks the beginning of one’s physical and spiritual journey in practicing the aspects of Islam. A Muslim strives to become one who the Quran terms as the faithful (mumin). Although this journey in becoming ‘faithful’ may be long, its rewards are numerous for those who embark on it with sincere will and intention.
Practicing Islam requires learning Islamic ideas, teachings, and practices, then adhering to them. Moreover, Islamic practice requires some sacrifice. However, the necessity of sacrifice should not be a deterrent. Prophet Muhammad states, “Whenever someone gives up something for the sake of God, God will replace it with something better.”
Sincerity of belief also develops over time. When Prophet Muhammad began spreading the message of Islam, some people came to him and informed him that they were believers in Islam. In reply, God revealed the following verse,
“Say [Muhammad to them]: ‘You believe not,’ but say, ‘We have submitted to Islam,’ for faith has not yet entered your hearts.” (49:14)
The successor to Prophet Muhammad, Imam Ali ibn Abi Talib, has described the dynamic process of following Islam, “I am defining Islam as no one has defined it before me: Islam is submission, submission is conviction, conviction is affirmation, affirmation is acknowledgement, acknowledgement is performance of obligations, and the performance of obligations is good deeds.”
 Imam Ali was Prophet Muhammad’s first-cousin and son-in-law. Since the age of six, Imam Ali was raised and educated by the Prophet.
 Nahj al-Balagha (The Peak of Eloquence), sermon #125. This work is a collection of sermons, lectures and sayings of Imam Ali complied by al-Sharif al-Radi (420 AH/972 CE).