Why is it important for Christians to avoid self-righteousness?

For Christians, self-righteousness can create a false sense of security that obstructs true faith in Christ. As seen in Mark 3:5, Jesus expresses anger and grief over the hardness of the Pharisees' hearts, which indicates that self-righteousness blinds individuals to their true condition before God. In contrast, believers are called to recognize their sinful nature and rely on Christ’s righteousness, thus maintaining a heart posture of humility and repentance. This aligns with the broader biblical narrative emphasizing that God opposes the proud and gives grace to the humble (James 4:6).