Complete submission to Allah (Tawhid)

يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱدْخُلُوا۟ فِى ٱلسِّلْمِ كَآفَّةً وَلَا تَتَّبِعُوا۟ خُطُوَٰتِ ٱلشَّيْطَـٰنِ ۚ إِنَّهُۥ لَكُمْ عَدُوٌّ مُّبِينٌ

O you who have believed, enter into Islām completely [and perfectly] and do not follow the footsteps of Satan. Indeed, he is to you a clear enemy.