The strategy of the devil from the beginning has been to peddle half-truths and establish these as the whole truth. Whenever half a truth is handled that way it becomes a lie, Genesis 3:5. That the eyes of our first parents would be opened was half a truth. That they will know what is good and evil was another half truth. And the devil presented these half truths as whole truths. The devil was trying to establish that God was lying when He said that they will die the moment they ate the forbidden fruit and secondly, he was trying to establish his lie that the real reason why God did not want them to eat the forbidden fruit was because they would become exactly like God.