How do we know God's justice and grace are true?

The nature of God encompasses perfect justice and boundless grace, seamlessly integrated as shown in Joel 2:13. It is essential to recognize that though God is a judge whose holiness demands justice — condemning sin — He is also gracious and merciful. Joel emphasizes that God 'repenteth him of the evil,' illustrating His willingness to extend mercy to those who repent and turn to Him. This dual characteristic of God offers assurance that while He does not overlook sin, He provides a means of reconciliation through Christ, exemplifying both His justice and grace.