Depart from me, you who work iniquity. Matthew 7:23
IN OTHER WORDS, GOD SAID, You Lived Your Own Life and Did Not Make Me God Over Your Life. That is what everything boils down to.
It is not just committing sin/breaking Gods law/commandments by reading what they were. It is entirely all in all. Obeying God at anything He says.
FOR AN EXAMPLE:
It is when God said yes do it now, and you say I'll do it but not now, tomorrow is more convenient, yes you will do it, but you are still doing your own thing, being your own God. That is iniquity.
It is also when God said yes do it now, and you say no, again, you are still doing your own thing, being your own God. That is iniquity.
It is when we live our own life and did not make Him God/Lord over our life. This is very serious.