'Nature' in the Bible

Among these [unbelievers] we all once lived in the passions of our flesh [our behavior governed by the sinful self], indulging the desires of human nature [without the Holy Spirit] and [the impulses] of the [sinful] mind. We were, by nature, children [under the sentence] of [God’s] wrath, just like the rest [of mankind].

for their [moral] understanding is darkened and their reasoning is clouded; [they are] alienated and self-banished from the life of God [with no share in it; this is] because of the [willful] ignorance and spiritual blindness that is [deep-seated] within them, because of the hardness and insensitivity of their heart.

that, regarding your previous way of life, you put off your old self [completely discard your former nature], which is being corrupted through deceitful desires,

and put on the new self [the regenerated and renewed nature], created in God’s image, [godlike] in the righteousness and holiness of the truth [living in a way that expresses to God your gratitude for your salvation].