Be not deceived. By your false teachers, and by their smooth and plausible arguments. This is an exhortation. He had thus far been engaged in an argument on the subject. He now entreats them to beware lest they be deceived -- a danger to which they were very liable from their circumstances. There was, doubtless, much that was plausible in the objections to the doctrine of the resurrection; there was much subtilty and art in their teachers, who denied this doctrine; perhaps there was something in the character of their own minds, accustomed to subtle and abstruse inquiry rather than to an examination of simple facts, that exposed them to this danger.
Evil communications. The word rendered "communications" means, properly, a being together; companionship; close intercourse; converse. It refers not to discourse only, but to intercourse, or companionship. Paul quotes these words from Menander, (in Sentent. Comicor. Gr. p. 248, ed. Steph.,) a Greek poet. He thus shows that he was, in some degree at least, familiar with the Greek writers. See "Acts 17:28".
Menander was a celebrated comic poet of Athens, educated under Theophrastus. His writings were replete with elegance, refined wit, and judicious observations. Of one hundred and eight comedies which he wrote, nothing remains but a few fragments. He is said to have drowned himself, in the fifty- second year of his age, B. C. 293, because the compositions of his rival, Philemon, obtained more applause than his own. Paul quoted this sentiment from a Greek poet, perhaps, because it might be supposed to have weight with the Greeks. It was a sentiment of one of their own writers, and here was an occasion in which it was exactly applicable. It is implied in this, that there were some persons who were endeavouring to corrupt their minds from the simplicity of the gospel. The sentiment of the passage is, that the intercourse of evil-minded men, or that the close friendship and conversation of those who hold erroneous opinions, or who are impure in their lives, tends to corrupt the morals, the heart, the sentiments of others. The particular thing to which Paul here applies it, is the subject of the resurrection. Such intercourse would tend to corrupt the simplicity of their faith, and pervert their views of the truth of the gospel, and thus corrupt their lives. It is always true that such intercourse has a pernicious effect on the mind and the heart. It is done,
(1.) by their direct effort to corrupt the opinions, and to lead others into sin.
(2.) By the secret, silent influence of their words, and conversation, and example. We have less horror at vice by becoming familiar with it; we look with less alarm on error when we hear it often expressed; we become less watchful and cautious when we are constantly with the gay, the worldly, the unprincipled, and the vicious. Hence Christ sought that there should be a pure society, and that his people should principally seek the friendship, and conversation of each other, and withdraw from the world. It is in the way that Paul here refers to, that Christians embrace false doctrines; that they lose their spirituality, love of prayer, fervour of piety, and devotion to God. It is in this way that the simple are beguiled, the young corrupted, and that vice, and crime, and infidelity spread over the world.