You belong to your father the devil, and you want to carry out your father's desires. He was a murderer from the beginning and does not stand in the truth, because there is no truth in him. When he speaks lies, he speaks from his own character, because he is a liar and the father of lies.
We should not be like Cain, who was of the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil, but the deeds of his brother were righteous.