Albert Barnes Commentary James 3:12

"Can a fig tree, my brethren, yield olives, or a vine figs? Neither [can] salt water yield sweet." — James 3:12 (ASV)

Can the fig-tree, my brethren, bear olive berries? Such a thing is impossible in nature, and equally absurd in morals. A fig-tree bears only figs; and so the tongue should express only one class of sentiments and emotions.

These illustrations are very striking and show the absurdity of what the apostle reproves. At the same time, they accomplish the main purpose he intended: to repress the desire of becoming public teachers without suitable qualifications. They show the power of the tongue; they show what a dangerous power it is for a man to wield who does not have the proper qualifications; they show that no one should put himself in the position to wield this power without such a degree of tested prudence, wisdom, discretion, and piety, that there will be a moral certainty that he will use it properly.