Commentaries:
Robertson's Word Pictures (NT)
Be not deceived (mh planasqe). Present passive imperative with mh, "stop being led astray" (planaw, common verb to wander, to lead astray as in Matthew 24:4 f.).
God is not mocked (ou mukthrizetai). This rare verb (common in LXX) occurs in Lysias. It comes from mukthr (nose) and means to turn the nose up at one. That is done towards God, but never without punishment, Paul means to say. In particular, he means "an evasion of his laws which men think to accomplish, but, in fact, cannot" (Burton).
Whatsoever a man soweth (o ean speirh anqrwpov). Indefinite relative clause with ean and the active subjunctive (either aorist or present, form same here). One of the most frequent of ancient proverbs (Job 4:8; Arist., Rhet. iii. 3). Already in II Corinthians 9:6. Same point in Matthew 7:16; Mark 4:26 f.
That (touto). That very thing, not something different.
Reap (qerisei). See on Matthew 6:26 for this old verb.
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