Do not be deceived, God is not mocked; for whatever a man sows, this will he also reap. For the one who sows to his own flesh shall from the flesh reap corruption, but the one who sows to the Spirit shall from the Spirit reap eternal life. And let us not lose heart in doing good, for in good time we shall reap if we do not grow weary “Do not be deceived, God is not mocked...” (Galatians 6:7a). The Greek word translated “mocked” is used only in this passage in the New Testament, though a closely related word is used of the soldiers who mocked Jesus. The word is “mukterizo” (mukthrzw), a verb in the present tense and middle voice. What this means is that literally Paul is saying that “God is not being mocked” by those who hold Him and His will in disdain. Literally, it means to “sneer at”, “turn up the nose at”, “treat with contempt”. It would describe the attitude of the criminal who thinks he has gotten away with something. He is in his fast sports car and being pursued by the police. As he crosses the border out of their jurisdiction, he stops his car, gets out and taunts them. He's not afraid of them; he's gotten away with it and they are powerless to do anything about it. He has escaped judgment and punishment. Many people evidently think they have escaped judgment for sins. They think that they are presently succeeding in mocking God with no consequence. What they fail to realize is that God allows such not because He is powerless to stop it, but because He has appointed a time to rectify things, and that time has not yet arrived. It will, but in the meantime even the most foolish outrages are permitted to continue with hopes that another heart can be reached by the gospel and a soul saved before the Day arrives (2 Peter 3:8-10). Those who think otherwise are being deceived. cowboy...

"Do not be deceived: God is not mocked, for whatever one sows, that will he also reap." the other version of the bible interprets that "you can never make a fool out of God." we can deceive men, but not God. we can always show pretentions to men, but not to God. He sees our heart and whatever abides inside it, can always be visible to God. If we choose to live a wicked lives, then we shall not inherit the kingdom of God. :)

From the bible. It refers to the ideas in people's heads about God himself. Many people think their idea of God is real. But in fact it isn't. "God is not mocked" means: no matter how distorted and ridiculous your idea of God is, it means nothing to God. God remains God.

I found an explanation from the internet, just for your reference :) Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap. 不要自欺，神是轻慢不得的。人种的是什么，收的也是什么。

Be not deceived” about this, “God is not mocked:” means that, if we should think that we can sow one thing and reap another, we would be thinking that we had the power to mock God—that is, to defy him by overriding his plans and arrangements. The Bible taught that men are very apt to think they can do that. They do so many things by means of their perseverance and determination that they are very apt to conclude they can do anything they choose, whether it pleases God or not; that they can go on trampling God’s laws under their feet as long as they choose, and still come out well.