'Righteous' in the Bible

Dear children, I write thus to you in order that you may not sin. If any one sins, we have an Advocate with the Father--Jesus Christ the righteous;

Since you know that He is righteous, be assured also that the man who habitually acts righteously is a child of His.

Dear children, let no one lead you astray. The man who acts righteously is righteous, just as He is righteous.

We are not to resemble Cain, who was a child of the Evil one and killed his own brother. And why did he kill him? Because his own actions were wicked and his brother's actions righteous.