What does it mean that God is not willing for any to perish but that all would come to repentance (2 Peter 3:9)?

TL;DR:

Second Peter 3:9 stresses God’s patience and mercy in delaying judgment so unbelievers have the opportunity to repent. God’s desire is that all would come to repentance, but the time to repent is not unlimited.

what does the bible say?

Second Peter 3:9 stresses God’s character and sovereignty in the timing of His judgment and His reason for waiting. Peter responds to the argument that God is "slow to fulfill his promise" of returning to judge the unrighteous by noting the delay is purposeful to allow more to repent (2 Peter 3:9). This theme of God’s desire for people to repent and His patience with them is found throughout the Bible. Sometimes it applies to judgment on this earth as opposed to the final judgment that Peter refers to. In the Old Testament, Ezekiel is one of many prophets God sent to His people to call them to repentance despite their frequent betrayals (Ezekiel 33:11). God had compassion on the Ninevites, sending Jonah to them to declare that He would destroy the city in forty days because of their sin. They repented, revealing the glorious results of God’s mercy (Jonah 3:6–10). The New Testament contains numerous references to God’s patience and mercy with sinners, the chief example being His Son, whom He sent in “the fullness of time … to redeem those who were under the law, so that we might receive adoption as sons” (Galatians 4:4–5). Many other Scriptures indicate that the delay in judgment is evidence of God’s patience with sinners and His desire for them to repent (Romans 2:4; 1 Timothy 2:3–4). Even if God’s final judgment doesn’t come before we die, we only have our lifetime to repent and develop a relationship with our Lord (Hebrews 9:27).

from the old testament

Psalm 86:15 asserts God’s patience and love, which 2 Peter 3:9 also conveys: “But you, O Lord, are a God merciful and gracious, slow to anger and abounding in steadfast love and faithfulness.” Psalm 86 praises God and entreats Him for help. The psalmist can ask God for mercy and salvation from his enemies because he knows that God is patient, loving, and faithful.
Ezekiel 33:11 is God’s call to repentance to the rebellious nation of Israel while they were in Babylonian captivity: “Say to them, As I live, declares the Lord God, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live; turn back, turn back from your evil ways, for why will you die, O house of Israel?” The “any” in 2 Peter 3:9 includes the wicked, as this passage from Ezekiel shows. God’s abundant lovingkindness is such that His desire is for the wicked to repent rather than face wrath.
This was also true of the Ninevites. Jonah’s resentment that God saved the Ninevites shows God’s mercy is greater, by far, than ours: “And he prayed to the Lord and said, ‘O Lord, is not this what I said when I was yet in my country? That is why I made haste to flee to Tarshish; for I knew that you are a gracious God and merciful, slow to anger and abounding in steadfast love, and relenting from disaster’” (Jonah 4:2). The Ninevites benefited from God’s patience, mercy, and forgiveness—as we all do.

from the new testament

Second Peter 3:9 discusses those who use God’s patience as a way of mocking Christians who faithfully await the Lord’s return: “The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance” (NKJV). Mockers misrepresent God’s patience in executing judgment to say He has forsaken His children (2 Peter 3:1–7). Peter makes it clear that far from forsaking us, the Lord is providing every opportunity for people to turn to Him before it is too late.
In Romans 2:3–4, Paul warns of the need for repentance, noting that God’s patience is opportunity for repentance: “Do you suppose, O man—you who judge those who practice such things and yet do them yourself—that you will escape the judgment of God? Or do you presume on the riches of his kindness and forbearance and patience, not knowing that God's kindness is meant to lead you to repentance?” Here Paul is explaining that rather than being a license to continue in sin, God's delay of judgment should be understood as an opportunity to turn away from sin.
First Timothy 2:3–4 iterates this theme of God’s patience in waiting for people to repent: “This is good, and it is pleasing in the sight of God our Savior, who desires all people to be saved and to come to the knowledge of the truth.” “This” refers to the preceding verses in which Paul urges prayers for “all people” (1 Timothy 2:1). This passage is additional evidence of God’s mercy, patience, and love for all.
Sadly, though, not all will repent even when given ample opportunity, as expressed in Revelation 20:14–15: “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.” On Judgment Day, those who rejected God will get what they wanted—eternal separation from Him (John 3:16–18, 36).

implications for today

In a world increasingly hostile to Christianity, many believers may plead along with John, “Come, Lord Jesus!” (Revelation 22:20). But then we think of loved ones who are unsaved, and we praise God for His patience. Even though we anxiously await our glorious, eternal home, we know some others in our lives love this world (1 John 2:15–17). Rather than getting drawn by them into the world, we should be a living testimony to those who are lost. Paul cautioned the Ephesians, “Look carefully then how you walk, not as unwise but as wise, making the best use of the time, because the days are evil” (Ephesians 5:15–16). That advice applies just as much today as then. Do you make the best use of your time? Witnessing to unbelievers, inviting them to church, and sharing your testimony are ways to make the most of the time God has given us on this earth. The world needs to know that God is loving and patient—but also just (Hebrews 4:12–13). The time to repent is not unlimited. Even if God’s final judgment doesn’t come before we die, we only have our lifetime to repent and develop a relationship with our Lord (Hebrews 9:27). What we do while on this earth matters. God uses us to reach the lost. We should never take that responsibility lightly.

understand

God delays judgment to provide opportunities for repentance.
God’s delay is intentional, allowing individuals time to turn from sin.
While God is patient, the opportunity for repentance is limited.

reflect

How does understanding God’s patience in delaying judgment shape your view of God?
In what ways can you personally reflect God’s mercy and patience in your interactions with those who may not believe?
How can you ensure that you are making the most of the opportunities you have in your life to share the message of repentance and salvation?

engage

How does the theme of God’s desire for repentance manifest in both the Old and New Testaments? What examples stand out to you?
In what ways do you think modern society misinterprets God's patience as indifference? How can believers address this misconception?
What practical steps can we take to be a living testimony to others about God’s love and the urgency of repentance in a world that often rejects these messages?