Albert Barnes Commentary Galatians 6:7

"Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap." — Galatians 6:7 (ASV)

But not deceived. That is, regarding your character and your hopes for eternity. This is a formula of introduction to an admonition that is especially weighty and important. It implies that there was danger that they would be deceived regarding their character. The sources of the danger were the corruption of their own hearts, the difficulty of knowing their true character, the instructions of false teachers, and so on. (See Barnes on 1 Corinthians 6:9).

God is not mocked. He cannot be imposed upon or mocked. He knows what our real character is, and He will judge us accordingly. The word rendered mocked, mukthērizō, means, properly, to turn up the nose in scorn; hence to mock, deride, or insult. The sense is that God cannot be imposed upon, nor can He be insulted with impunity or successfully.

To mock properly means:

1. To imitate or mimic; to imitate in contempt or derision.
2. To deride, laugh at, or ridicule.
3. To defeat, delude, or disappoint.
4. To fool or tantalize (Webster).

In this context, it cannot mean to imitate or mimic. Instead, it refers to the principles of the Divine administration and must mean that God’s principles cannot be treated with contempt or successfully evaded. People cannot hope to delude or impose upon God. His principles of government are settled, and they cannot impose upon Him.

What this refers to here is not entirely clear. In the connection in which it stands, it seems to refer to the support of the ministers of the gospel. Paul introduces the general principle that as a man sows, so will he reap, to show them what will be the effect of a liberal and proper use of their property.

If they made proper use of it—if they employed it for benevolent purposes, if they appropriated what they should to the support of religion—they would reap accordingly. God could not be imposed upon regarding this. They could not make Him think that they had true religion when they were sowing to the flesh, spending their money on acquiring pleasure, and in luxury and vanity.

No zeal, however ardent; no prayers, however fervent or long; no professions, however loud, would impose upon God. To offer such prayers, to manifest such zeal and such strong professions while the heart was with the world, and while they were spending their money on everything else but religion, was mocking God.

Alas, how much mockery of God like this still prevails! How much occurs when people seem disposed to make God believe they are exceedingly zealous and devoted, while their hearts are truly with the world! How many long prayers are offered, how much zeal is shown, how many fervent professions are made, as if to make God and humanity believe that the heart is truly engaged in the cause of religion, while little or nothing is given to benevolent causes.

Meanwhile, ministers of religion are allowed to starve, and the “loud professor” rolls in wealth, distinguished by luxurious living, showy clothing, splendid carriages, and extravagance in parties of pleasure! Such professors attempt to mock God. They are really sowing to the flesh; and of the flesh they must reap corruption.

For whatsoever a man soweth, etc. (See Barnes on 2 Corinthians 9:6).

This figure is taken from agriculture. A man who sows wheat will reap wheat; he who sows barley will reap barley; he who sows cockle will reap cockle. Every kind of grain will produce grain like itself. So it is regarding our works. He who is liberal will be dealt with liberally; he who is righteous will be rewarded; he who is a sinner will reap according to his deeds.