I've recently been watching workout advice and the gentleman who was in the video said the phrase "be in the gym but not of the gym" and initially I thought I understood that but after pondering a while about it I came to a conclusion that I did not.
I've done some googling and found few bible references of the phrase "be in the world but not of the world" but couldn't make sense of their philosophical explanations.
So What does it mean to "be in [something] but not of [something]" ?