The first pillar of Islam is to pronounce the Shahada:
Ash hadu anla ilaha il’Allah, wa ash hadu anna Muhamadar rasulullah
I bear witness, that there is no God except Allah, and I bear witness that Muhammad is the Messenger of Allah
The belief and testimony that there is no God except Allah and that Muhammad is His messenger. The definition of ‘shahada’ is to express something with the tongue and believe it with the heart. But what does it mean to believe in Allah? Believing in Allah entails accepting His existence, knowing His attributes and believing in them. It is obligatory for every Muslim to believe in the existence of Allah, that He is prior to the beginning of time and has continuity beyond the end of time. In that He is unique, He is one, He is self-sufficient, independent, He needs absolutely nothing, in that He is different from everything that He has created, that He is The Living, The Powerful, The Wise, The One who has Will over all things, The One who possesses hearing, sight and speech. These are some of the attributes of Allah, in Whom belief is obligatory for us, and therefore it is also obligatory to deny all the opposites of these attributes. By knowing and believing in these attributes, we are confirming the first part of the Shahada, which refers to the fact that Allah is the only God: Ash hadu anla ilaha il’Allah, I bear witness, that there is no God except Allah.
The second part is to bear witness that the Prophet Muhammad is the last of the messengers, the Seal and culmination of all the prophets, that he was sent by The Creator to both men and jinn, that he ratified the messengers that preceded him. , and that upon him Allah sent down the Qur’an as a guide for men: wa ash hadu anna Muhamadar Rasulullah, and I testify that Muhammad is the Messenger of Allah.
Accepting Islam consists of affirming the shahada with sincere and free belief before Muslim witnesses and from that moment on the other four worship practices or pillars of Islam become obligatory: Salat, Zakat, Ramadan Fasting and Pilgrimage.