Albert Barnes on Matthew 6:28-29

The fourth consideration is taken from the lilies of the valley. Watch the growing of the lily. It toils not, and it spins not. Yet night and day it grows. With a beauty which the most splendid monarch of the East never knew, it expands its blossom and fills the air with fragrance. Yet this beauty is of short continuance. Soon it will fade, and the beautiful flower will be cut down and burned. God so little regards the bestowment of beauty and ornament as to give the highest adorning to this which is soon to perish. When he thus clothes a lily--a fair flower, soon to perish--will he be unmindful of his children? Shall they--dear to his heart and imbued with immortality--lack that which is proper for them, and shall they in vain trust the God that decks the lily of the valley? He will much more clothe you.

Even Solomon in all his glory, etc. The common dress of eastern kings was purple. But they sometimes wore white robes. See Est 8:15, Dan 7:9. It is to this that Christ refers. Solomon, says he, the richest and most magnificent king of Israel, was not clothed in a robe of so pure a white as the lilly of the valley.