'Nature' in the Bible

If we [freely] admit that we have sinned and confess our sins, He is faithful and just [true to His own nature and promises], and will forgive our sins and cleanse us continually from all unrighteousness [our wrongdoing, everything not in conformity with His will and purpose].

For the things in the world--the cravings of the earthly nature, the cravings of the eyes, the show and pride of life--they all come, not from the Father, but from the world.

No one who is born of God [deliberately, knowingly, and habitually] practices sin, because God’s seed [His principle of life, the essence of His righteous character] remains [permanently] in him [who is born again—who is reborn from above—spiritually transformed, renewed, and set apart for His purpose]; and he [who is born again] cannot habitually [live a life characterized by] sin, because he is born of God and longs to please Him.

By this the children of God and the children of the devil are clearly identified: anyone who does not practice righteousness [who does not seek God’s will in thought, action, and purpose] is not of God, nor is the one who does not [unselfishly] love his [believing] brother.

and not be like Cain, who was of the evil one and murdered his brother [Abel]. And why did he murder him? Because Cain’s deeds were evil, and his brother’s were righteous.