Even the casting of the reprobate into the Lake of Fire is an act of mercy!
(Arthur Pink, "The Mercy of God" 3 pages)
It is pure sovereign grace which alone determines the exercise of divine mercy. God expressly affirms this fact in Romans 9:15, "I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion. It does not, therefore, depend on man's desire or effort, but on God's mercy."
It is not the wretchedness of the creature which causes Him to show mercy, for God is not influenced by things outside of Himself as we are. If God were influenced by the abject misery of leprous sinners, He would cleanse and save all of them. But He does not. Why? Simply because it is not His pleasure and purpose so to do.
Still less is it the merits of the creatures which causes Him to bestow mercies upon them, for it is a contradiction in terms to speak of meriting mercy. "Not by works of righteousness which we have done, but according to His mercy He saved us" (Titus 3:5)—the one standing in direct antithesis to the other.
The merits of Christ make it possible for God to righteously bestow spiritual mercies on His elect—justice having been fully satisfied by the Surety! Divine mercy arises solely from God's imperial pleasure.
Though it is true, blessedly and gloriously true, that God's mercy "endures forever"—yet we must observe carefully the objects to whom His "saving mercy" is shown.
Even the casting of the reprobate into the Lake of Fire is an act of mercy! The punishment of the wicked is to be contemplated from a threefold viewpoint:
1. From God's side, the punishment of the wicked is an act of justice, vindicating His honor. The mercy of God is never shown to the detriment of His holiness and righteousness.
2. From their side, it is an act of equity, when they are made to suffer the due penalty of their iniquities.
3. But from the standpoint of the redeemed, the punishment of the wicked is an act of unspeakable mercy. How dreadful would it be if the present order of things, when the children of God are obliged to live in the midst of the children of the Devil, should continue forever! Heaven would at once cease to be Heaven, if the ears of the saints still heard the blasphemous and filthy language of the reprobate. What a mercy that in Heaven, "Nothing evil will be allowed to enter, nor anyone who practices shameful idolatry and dishonesty—but only those whose names are written in the Lamb's Book of Life!" Revelation 21:27
But let our final thought be of God's spiritual mercies unto His own people—the riches thereof transcend our loftiest thought. "For as the heaven is high above the earth, so great is His mercy toward those who fear Him" (Psalm 103:11). None can measure it.
The elect are designated "vessels of mercy." Romans 9:23
It is divine mercy which quickened them when they were dead in sins. Ephesians 2:4-5
It is God's mercy which saves them. Titus 3:5
It is His abundant mercy which begat them unto an eternal inheritance which can never perish, spoil or fade! 1 Peter 1:4
Time would fail us to tell of His preserving, sustaining, pardoning and supplying mercies!
Unto His own, God is "the Father of mercies and God of all comfort!" 2 Corinthians 1:3