Why is the grief over sin important for Christians?

In the narrative of Esther, Mordecai's grieving symbolizes the Holy Spirit's sorrow over sin, which is essential for Christians. The indwelling of the Holy Spirit makes us sensitive to our sinfulness, emphasizing our need for repentance. According to Ephesians 4, while we are assured of our justification in Christ, we are cautioned not to grieve the Holy Spirit through our actions. This grieving leads us to seek forgiveness and to rest in Christ’s finished work on the cross, where He took upon Himself the wrath we deserved, showcasing the profound nature of God’s mercy.