What is exactly SIN? According to heavenly father?

It's not a sin, what is being done by the law of nature, but when one is doing something bad by free will. Eat food is not a sin, but sinful is to eat without thanksgiving and incontinent; not a sin just to look, but a sin to look with envy, pride, insatiable, lust; not a sin to listen quietly, but a sin to listen with anger, not a sin to make the tongue thanking and praying, but sin is to allow it to slander and condemn, not a sin to trouble hands begging for alms, but a sin to allow the theft and murder. Thus are each member of sins, when we by free will are doing evil instead of good, contrary to the will of God. Sin separates from the God and leads to the death.