Muawiyah ibn Ammar asked Imam Sadiq about this verse “And to Allah belong the best names, so invoke Him by them.” (7:180). The Imam answered

 “I swear to God that we are the Lord’s Good Names so that God does not accept any deed of humans unless they know us

Usul al-Kafi, chapter: Al-navader

Indeed, what kind of knowledge is this? Which is so important? We’ll mention it later