I think it mean to follow Jesus you need complete concentration,you can not serve God and at the same time worship the devil.

Iniquity means some that is not pure in heart, thought and in character, e.g an immoral behavior.

Christianity means living a life that emulates Christ life, understanding the bible and walking in obedience to it's teaching. 

A mother cat can not kill her kittens if touched, but she can move them from the present position to an other position by carrying them with their mouth.