Mustard
is mentioned in (Matthew 13:31; 17:20; Mark 4:31; Luke 13:19; 17:6) It is generally agreed that the mustard tree of Scripture is the black mustard (Sinapis nigru). The objection commonly made against any sinapis being the plant of the parable is that the reed grew into "a tree," in which the fowls of the air are said to come and lodge. As to this objection, it is urged with great truth that the expression is figurative and Oriental, and that in a proverbial simile no literal accuracy is to be expected. It is an error, for which the language of Scripture is not accountable, to assert that the passage implies that birds "built their nests" in the tree: the Greek word has no such meaning; the word merely means "to settle or rest upon" anything for a longer or shorter time; nor is there any occasion to suppose that the expression "fowls of the air" denotes any other than the smaller insessorial kinds--linnets, finches, etc. Hiller's explanation is probably the correct one,--that the birds came and settled on the mustard-plant for the sake of the seed, of which they are very fond. Dr. Thomson also says he has seen the wild mustard on the rich plain of Akkar as tall as the horse and the rider. If, then, the wild plant on the rich plain of Akkar grows as high as a man on horseback, it might attain to the same or a greater height when in a cultivated garden. The expression "which is indeed-the least of all seeds" is in all probability hyperbolical, to denote a very small seed indeed, as there are many seeds which are smaller than mustard. The Lord in his popular teaching," says Trench ("Notes on Parables", 108), "adhered to the popular language;" and the mustard-seed was used proverbially to denote anything very minute; or may mean that it was the smallest of all garden seeds, which it is in truth.