Galatians 6:7 says that God is not mocked; what does that mean?

from the old testament

• The Old Testament teaches us that the type of person who mocks is a wicked, arrogant fool (Psalm 1:1, 5–6; Psalm 74:22–23; Psalm 119:51; Proverbs 1:22; Proverbs 15:12).
• Scripture uses many synonyms for mockery, including scoffing, reproaching, deriding, spurning, reviling, and so forth (Psalm 74:10, 22–23; Proverbs 1:22; Isaiah 37:23). To mock means to make fun of something or someone. In the case of God, to mock Him is to deny and ignore Him, His commands, and His promises (Proverbs 1:24–25; see Romans 2:4).
• The fool mocks God (Psalm 74:22; Proverbs 1:22; Proverbs 14:9).
• The mocker is described as wicked (Psalm 1:1). The Psalmist is saying that the wicked are the ones who scoff (mock). Notice that the wicked are also acting like fools because, “the wicked will not stand in the judgment …. the way of the wicked will perish” (Psalm 1:5a, 6b).
• Asaph asks God to take vengeance against the wicked, saying, “Arise, O God, and defend Your cause; remember how the foolish scoff at you all the day! Do not forget the clamor of your foes, the uproar of those who rise against You, which goes up continually” (Psalm 74:22–23). A mocker of God is a fool because He is mocking the one in the position of strength.
• Wicked fools mock God by hating true knowledge (Proverbs 1:22; c.f., 13:1). Notice that the mocker prefers scoffing God rather than listening to Him!
• Because the wicked fool will not listen, he and she are also unteachable. “A scoffer does not like to be reproved, he will not go to the wise” (Proverbs 15:12). “Reprove” means to correct. A scoffer does not listen to wise correction.
• God will not be mocked (Psalm 2:4-5).
• Proverbs said something similar. “Because I called and you refused to listen, I stretched out my hand and no one heeded; because you have ignored all my counsel and would have none of my reproof; I will also laugh at your calamity; I also will laugh at your calamity” Proverbs 1:24–26).
• As the source of wisdom, God calls us to listen to Him (Proverbs 1:23).

from the new testament

• Galatians 6:7 says, “Do not be deceived, God is not mocked; for whatever one sows, that he will also reap.” Similar to the Proverbs 1:24–26 passage, the result of our foolishness is that we get what we deserve. In the next verse Paul says, “For the one who sows to his own flesh will from the flesh reap corruption, but the one who sows to the Spirit will from the Spirit reap eternal life” (Galatians 6:8). The one who mocks God mocks His counsel and relies on his own wisdom. The result is corruption and, ultimately, death. Conversely, the wise man or woman who listens to God, obeys Him and His Son and will have the ultimate end of eternal life.
• As the Son of God and perfect image of God (Colossians 1:15), Jesus was regularly mocked. Prior to His crucifixion, Herod showed that he was a fool, mocking Him. “And Herod with his soldiers, treated Him with contempt and mocked Him, then arraying Him in splendid clothing, he sent Him back to Pilate” (Luke 23:11). As they were sending the Son of God to death, they were mocking the one who would return to judge them (Revelation 1:7).
• While He was on the cross, the mockery did not end. “One of the criminals who were hanged railed at Him, saying, ‘Are You not the Christ? Save Yourself and us!’” (Luke 23:39).
• The rulers also mocked Jesus. “In the same way the chief priests also, along with the scribes and elders, were mocking Him and saying, ‘He saved others; He cannot save Himself. He is the King of Israel; let Him come down now from the cross, and we will believe in Him’” (Matthew 27:42).
• Before His death, Jesus told His disciples that they, too, would be mocked. “If the world hates you, you know that it has hated Me before it hated you. If you were of the world, the world would love its own; but because you are not of the world, but I chose you out of the world, therefore the world hates you. Remember the word that I said to you, ‘A servant is not greater than his master.’ If they persecuted Me, they will also persecute you; if they kept My word, they will keep yours also. But all these things they will do to you on account of my name, because they do not know him who sent Me” (John 15:18–21). People mocked Jesus because He showed them God, and they will mock believers when we show them Christ.
• Peter and the disciples, during the first sermon after the birth of the church, received mockery. They were talking in a variety of languages by the power of the Holy Spirit, with many amazed that they could speak their own language (Acts 2:7–8). However, despite the evidence to the power working through them, some mocked them as being drunk (Acts 2:13).
• Paul experienced mockery when He spoke about the true God to the polytheistic sophists of Athens. He explained that Jesus had been risen from the dead, meaning He was God and would judge the world. (Acts 17:32a).
• The reason believers are mocked today is because “the word of the cross is foolishness to those who are perishing” (1 Corinthians 1:18a). That is, mockers are the fools who are headed for damnation and unable to understand the Gospel (1 Corinthians 2:14). It is foolishness to them, which is why they mock it.
• Peter anticipated this mockery (2 Peter 3:3–6). In this passage, Peter points out that God already fired a “warning shot” across humanity’s bow by destroying most of the world in judgment with His flood. Mocking that God is the height of foolishness!
• God’s hatred for mockery is seen in Acts 5:1–11, where Ananias and Sapphira lied about their offering, pretending to give it all while keeping some back. By trying to deceive the church, they mocked God, assuming He wouldn’t notice their hypocrisy. Peter exposed their lie, saying, “You have not lied to man but to God” (Acts 5:4). Both fell dead as a result (Acts 5:5, 10), showing that mocking God through deceit brings serious judgment.
• Mockers who escape punishment now face certain future judgment. Paul warns that ignoring God’s kindness leads to storing up wrath for the day of His righteous judgment (Romans 2:4–6). Mockery is stubborn refusal to heed God’s wisdom, resulting in wrath and condemnation for all who do evil (Romans 5:8–9).
• At the end of time, God will open books that contain the deeds of both the great and the small (Revelation 20:11–12) and judge the mockers who have rejected Him. He will punish them eternally for their arrogant, fool-hearted response to His mercy (Revelation 20:15). God will not be mocked!

implications for today

God is a patient God, very rarely destroying people immediately when they sin. This grace—this delay of judgment—leads many to openly mock Him thinking that there are no ramifications for what they do. The Bible calls them fools.

But what about us—we who believe in God and trust in His Son, Jesus? The Ananias and Sapphira story should cause us to be very careful. When we sin, for that one moment we say that there will be no consequences to that sin. By saying that, we are thumbing our nose at God—we are mocking Him. It is true that believers will not be eternally punished in Hell because Jesus has already paid for our sin, past, present, and future. However, God does discipline us (Hebrews 12:4–10). He will not be mocked, even by His children! Also, we learn that we will also be judged at the end of time, gaining or losing rewards for what we did in this life (2 Corinthians 5:10). Our disobedience will be judged because God will not be mocked.

It is true that no one is perfect—that is why we need Jesus! However, being saved by Jesus’ righteous life and death is also not grounds for us to become complacent about sin (Romans 6:1–2). Of all people, we who have been saved should be the last ones mocking Him!