How can minor shirk and minor disbelief be magnified in people's hearts, and how can they be instilled with fear of what these lead to, while emphasizing that they do not expel one from the fold of Islam?

Underestimating minor shirk is ignorance and delusion, for it is a grave sin, greater than major sins, and it can be a means to major shirk. Ibn Mas'ud said: "For me to swear by Allah falsely is more beloved to me than to swear by other than Him truthfully," because swearing by other than Allah is a type of shirk. Underestimating sins in general, and shirk in particular, is extremely dangerous.