How do we know God is just in justifying sinners?

The justice of God in justifying sinners is established through the sacrificial work of Christ. As stated in 2 Corinthians 5:21, God made Christ to be sin for us, enabling believers to become the righteousness of God in Him. At the cross, a divine exchange occurred where Christ, innocent and pure, took on our sin, and we were clothed with His righteousness. This substitution is key to understanding how God can remain just while justifying the ungodly. It reflects His holiness and righteousness, ensuring that no unrighteousness resides in Him.