Whenever someone is struggling with the concept of billions of people being eternally separated from God in hell, sooner or later somebody will offer Isaiah 55:8-9:
For my thoughts are not your thoughts, neither are your ways my ways," declares the Lord. "As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts."
The idea of invoking this passage is to say that God must have wonderful, glorious purposes in allowing most of His creatures to suffer in hell forever, but we can’t comprehend them because our minds are so tiny compared to his.
However, a closer look at Isaiah 55 shows that the passage is saying nothing of the sort—in fact, virtually the opposite. The Israelites wanted their enemies to be punished and non-Jews to be excluded from God’s people, but God, contrary to their expectations, offers abundant mercy to all. What the Israelites can’t fathom is how vast and inclusive His mercy is.
The theme of Isaiah 55 is in verse 1: “Come, all you who are thirsty,” and in verse 3: “Give ear and come to me; hear me that your soul may live.” The verse immediately preceding the often-quoted ones says,
Let the wicked forsake his way and the evil man his thoughts. Let him turn to the Lord, and he will have mercy on him, and to our God, for he will freely pardon.
What we cannot comprehend is how freely He pardons!
Verses 10-11 go on to say that, like the rain and snow that water the earth so it yields bread, so God’s Word will achieve the purpose for which He sent it. His purpose in revealing Himself is that all mankind might know and honor Him.
The theme of God’s desire to bless continues through chapter 55 and into chapter 56. Verses 12 and 13 of chapter 55 talk about joy, peace, and song, and the fact that pine trees and myrrh will grow instead of thorns and briers. “This will be for the Lord’s renown,” not billions of people suffering eternal punishment.
Chapter 56 invites foreigners to partake of God’s goodness:
Let no foreigner who has bound himself to the Lord say, "The Lord will surely exclude me from his people” (verse 3).
God promises to give to faithful foreigners “a memorial and a name . . . an everlasting name that will not be cut off” (5). He will bring these foreigners to His holy mountain and give them joy in His house of prayer, “for my house will be called a house of prayer for all nations” (7).
So this passage is really talking about how inclusive God’s mercy is (which the Israelites couldn’t comprehend), not that He excludes vast numbers of people from His kingdom and that we just have to accept it. He wants to keep on gathering people to Himself: “The Sovereign Lord declares—he who gathers the exiles of Israel: I will gather still others to them besides those already gathered” (56:8). The wicked can’t come in while they remain in their wickedness, but God urges them to turn to Him so He can have mercy on them and freely pardon them.
A similar thought is expressed in Psalm 145: “Great is the Lord and most worthy of praise; his greatness no one can fathom” (3). The chapter talks about His mighty acts and glorious splendor and majesty and power and dominion (4-6, 10-13), and especially about His “abundant goodness” (7-9, 13ff).
He is gracious and compassionate, slow to anger and rich in love (8).
He is good to all and has compassion on all he has made (9).
He upholds all those who fall and lifts up all who are bowed down (14).
He is loving toward all he has made (13, 17).
His wonderful love, which is so much higher than our ways, is what humans cannot fathom!