The cross of Christ was both an accomplishment and a demonstration. It supplied atonement, but also illustrated God’s justice. In vs25&26 Paul has some extremely important things to say about divine justice 

God’s justice is an important Biblical theme. It is especially prominent in the songs in the Book of Revelation. It is particularly interesting to see that Revelation ties God’s justice and vindication to the death of Jesus on the cross and the fairness of His judgments. 

The songs of Revelation 4 and 5 begin to build the theme when they repeatedly declare God’s worthiness in the context of the heavenly throne room/sanctuary. “Worthy art thou, O Lord and God, to receive glory and honour and power” (Rev.4:11RSV). In chapter 5 John weeps because he can find no one “worthy” to unseal the mysterious scroll. Then the Lamb enters, and the heavenly beings sing “a new song, saying, ‘worthy art Thou to take the scroll and open its seals, for Thou waste slain and by Thy blood didst ransom men for God” (Rev.5:9, RSV). The numberless host of heaven then proclaim “with a loud voice, Worthy is the Lamb who was slain, to receive power and wealth and wisdom and might and honour and glory and blessing!” (v12 RSV). 

We should note that those passages directly relate the “worthiness” of Christ to unseal the scroll of salvation history to His atoning sacrifice. It was that sacrifice, Paul claims in Rom.3:24-26, that shows God’s righteousness in justifying sinners. 

A second major round of Revelation’s doxologies appears in the judgment scene of the seven last plagues. “Just and true art Thou in these Thy judgments,” the angel proclaims in Rev.16:5 (RSV; see also Rev.16:7; 15:3,4). 

The third round occurs at the Second Advent. Rev.19 reads, “Hallelujah! Salvation and glory and power belong to our God, for His judgments are true and just” (Rev.19:1, 2, RSV; cf. v11).

The justice of God is not at the edge of the great controversy between God and the devil – it is at the very centre. He must truly demonstrate that He is love in everything He does.