God is good and right when He judges sin and saves sinners. The Bible has many paradoxes within it, things that seem to be opposing ideas but that actually work together in the mind and plan of God. While it might be easier for us to understand God as either just or merciful, the biblically correct to understand Him is not as either/or but as both/and. The justice and mercy of God are on display through the cross of Jesus where His sacrifice appeases the justice of God and His mercy is dispensed to those in desperate need. The justice and mercy of God are also on display through Revelation 7 where we see vast multitudes receiving salvation even as the judgment of God falls on the rebellious unbelieving world.