The declaration 'Ash-hadu an la ilaha illallah wa ash-hadu anna Muhammadan Rasulullah' is associated with which pillar of Islam?

The Shahada is the Islamic declaration of faith, which translates as 'I bear witness that there is no god but Allah and I bear witness that Muhammad is the Messenger of Allah.' It is the first and most fundamental pillar of Islam. Uttering the Shahada with sincere belief is what makes a person a Muslim.