Imaam Ibnul Qayyim (rahimahullaah) said: A slave (of Allaah) will not (truly actualize the statement) ”you alone we worship (O Allaah)”, except by way of two fundamental principles: The first of them is to follow the Messenger (sallal-laahu-alayhi-wasallam) and the second is sincerity to the (only true object) of worship (i.e. Allaah) [source-page: 68تهذيب المدارج ]