Can the tree, my brethren, bear olive berries? either a vine, figs? The same tree cannot ordinarily bring forth fruit of different kinds, (on the same branch, whatever it may on different, by ingrafting), much less contrary natures: see Matthew 7:16-18. So can no fountain both yield salt water and fresh; or, neither can a salt fountain yield fresh water; but the scope is still the same as in our reading. The apostle argues from what is impossible, or monstrous, in naturals, to what is absurd in manners: q.d. It is as absurd in religion, for the tongue of a regenerate man, which is used to bless God, to take a liberty at other times to curse man, as it would be strange in nature for the same tree, on the same branch, to bear fruits of different kinds; or the same fountain at the same place to send forth bitter water and sweet.
Related Commentaries of James 3:12
James 3:12
12 Can the fig tree, my brethren, bear olive berries? either a vine, figs? so can no fountain both yield salt water and fresh.