Human nature, from the moment we are clothed in flesh, carries a tendency toward evil, driven by self-satisfaction and selfishness. As children, we learn to fulfill the desires of our flesh, and by the time we think rationally, we already lean toward evil due to this inherent pull. Jesus, in Matthew 7:11, plainly calls us evil, using a term that suggests active, rebellious wickedness akin to that of satan. He contrasts our morally corrupt nature, which opposes God, with the transcendent goodness of our Father in heaven, highlighting that even in our evil state, we occasionally do good for our children. This evil within us stems from the choice made in the Garden of Eden, where mankind opted to define good and evil through trial and error, fixing us under the curse of sin. Despite being called by God and given the Holy Spirit, we remain a mixed bag, bearing a nature inclined toward evil and rebellion, yet challenged to transform from evil to good by overcoming internal sin. The true battle lies in recognizing and fighting the evil within ourselves, as Jesus emphasizes in Mark 7:14-16, pointing out that the sins defiling us originate from inside. Our spiritual duty is to acknowledge, face, and subdue these internal evils that we conceive and nurture within.

God has declared the state of the human heart in stark terms. In Genesis 6:5, the Lord saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. Even after the Flood, which wiped mankind almost completely from the planet, the human heart remained unchanged. In Genesis 8:21, the Lord said in His heart that the imagination of man's heart is evil from his youth. This persistent evil nature is echoed in David's words in Psalm 51:5-6, where he acknowledges being born into a sinful world, surrounded by sin from conception, and expresses a desire for God to change his nature from evil to good, from lies to truth. The Old Testament further asserts this reality of human nature. Ecclesiastes 9:3 states that the hearts of the sons of men are full of evil, with madness in their hearts while they live, until they go to the dead. Even the best among men, considered just, cannot escape this taint, as Solomon notes in Ecclesiastes 7:20 that there is not a just man on earth who does good and does not sin. This corrupted nature ensures that even deeds thought to be right ultimately lead to death, revealing the inherent evil within the human heart.

The human heart, as the seat of man's intellect, emotions, attitudes, and inclinations, is deceitful above all things and desperately wicked, as God declares in Jeremiah 17:9. This profound truth reveals that no one can fully know the depths of their own heart's corruption, for it deceives most of all the person who possesses it. Despite God's forgiveness at baptism, the evil nature within us, built up over years of wrong habits and attitudes, remains unchanged and continues to influence every decision. This internal battle rages on, requiring a daily fight to overcome the lingering evils from our past and to transform into Christ's image. God alone truly knows our real character, and we must strive to recognize the corruption within our hearts, understanding that self-deception can lead to self-righteousness and pride. Without this acknowledgment, our spiritual growth can stall, turning us away from God's path. Like the publican in the parable, who humbly recognized his own wickedness, we must approach God with the awareness of our sinful nature, seeking His mercy. Evil within us must not be taken lightly, for it is a constant force we are called to confront and conquer inwardly.