'Righteous' in the Bible

If we confess our sins, he is faithful and righteous to forgive us our sins, and to cleanse us from all unrighteousness.

My little children, these things write I unto you that ye may not sin. And if any man sin, we have an Advocate with the Father, Jesus Christ the righteous:

If ye know that he is righteous, ye know that every one also that doeth righteousness is begotten of him.

My little children, let no man lead you astray: he that doeth righteousness is righteous, even as he is righteous:

not as Cain was of the evil one, and slew his brother. And wherefore slew he him? Because his works were evil, and his brother's righteous.