Imam al-Bukhariyy related that the Messenger of Allah, sallallahu ^alayhi wa sallam, said: “The best of the deeds is believing in Allah and His Messenger.”
Believing in Allah and His Messenger MuHammad, sallallahu ^alayhi wa sallam, is the best of the deeds and most loved by Allah, ta^ala.
The good deeds like prayers, fasting, pilgrimage, and zakah, are only valid if one believes in Allah and His Messenger. The good deeds are not accepted from a blasphemer.
“Ashhadu alla ilaha illallah wa ashhadu anna MuHammadar Rasulallah” means: “I testify that no one is God except Allah and that MuHammad is His Messenger, ^ala MuHammad, sallallahu ^alayhi wa sallam.”