The first step towards the implementation of faith in Islam is to declare it. This is the first pillar of Islam. The declaration of faith or Kalima Shahadah carries the essence of Islam:
اَشْہَدُ اَنْ لَا اِلٰہَ اِلَّا اللّٰہُ وَ حْدَہٗ لَا شَرِیْکَ لَہٗ وَ اَشْھَدُ اَنَّ مُحَمَّدًا عَبْدُہٗ وَ رَسُوْلُہٗ I bear witness that there is none worthy of worship except Allah. He is One and has no partner. And I bear witness that Muhammad is His Servant and Messenger.
اَشْہَدُ اَنْ لَا اِلٰہَ اِلَّا اللّٰہُ وَ حْدَہٗ لَا شَرِیْکَ لَہٗ وَ اَشْھَدُ اَنَّ مُحَمَّدًا عَبْدُہٗ وَ رَسُوْلُہٗ
I bear witness that there is none worthy of worship except Allah. He is One and has no partner. And I bear witness that Muhammad is His Servant and Messenger.
audio
In the early days of Islam, the reciting of the Shahdah marked the act of conversion to the new faith.