Good News! Mercy and Justice is Reconciled

God is just and justice demands that sinners should be punished for their sins.
Do not be deceived: God is not mocked, for whatever one sows, that will he also reap. (Galatians 6:7 ESV)
For the wages of sin is death,  (Romans 6:23a ESV)

But God is merciful. God is love.
Have I any pleasure in the death of the wicked, declares the Lord GOD, and not rather that he should turn from his way and live? (Ezekiel 18:23 ESV)
Anyone who does not love does not know God, because God is love. (1 John 4:8 ESV)

So how does a just and righteous God reconcile justice with mercy? How can He love us and not punish us for our sins and yet remain just?
But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. (Romans 5:8 NASB)
For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit, (1 Peter 3:18 ESV)

But when you reject God's pardon and love in the form of Christ, what remain for you will be God's justice and the wrath of God on sin and sinners.
How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard him; (Hebrews 2:3 KJV)
Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved. (Acts 4:12 KJV)
And I saw the dead, great and small, standing before the throne, and books were opened. Then another book was opened, which is the book of life. And the dead were judged by what was written in the books, according to what they had done. And the sea gave up the dead who were in it, Death and Hades gave up the dead who were in them, and they were judged, each one of them, according to what they had done. Then Death and Hades were thrown into the lake of fire. This is the second death, the lake of fire. And if anyone’s name was not found written in the book of life, he was thrown into the lake of fire. (Revelation 20:12-15 ESV)