I. Jonah's gourd was all but certainly the palm-Christ, so-called because it is a five-leaved plant, one leaf of which outspread resembles a man's hand. It was thought to represent the hand of Christ. This plant is indigenous in nearly all the Eastern countries. It grows to the height of eight, ten, twelve feet. It has but one leaf for a branch, but the branches are numerous, and the leaves are broad. Branch rising above branch, nothing could be better adapted for making a screen and casting a relieving shadow. It was a quickly growing plant, which sprang up during the forty days, and was ready with its shade for the prophet's time of need. By a poetic figure it is called, in the tenth verse, "the son of the night."
II. Why was Jonah so exceeding glad of the gourd? (i) Partly, no doubt, for the simplest and most obvious reason because it was an immense physical relief and protection. (ii) The gourd was a gift from God to the prophet, and accepted by him as such. He sat there under its shadow with great delight. (iii) He would probably take it as a Divine indication that he had done right in waiting to see what would become of the city.
III. It is impossible to help "moralizing," as some would call it, on the worm and the gourd. They are felt universally to be emblems too faithful of the swift-coursing, closely-linked joy and sorrow of this mortal life. (i) The fine plant, leafy green, types so well our comforts, successes, joys. (ii) The single day of shade it furnished the heated prophet speaks touchingly of the transiency of our pleasures. (iii) The worm reminds us that a small and mean creature may be a very formidable enemy. (iv) The place of. its operation, under the soil, shows us how powers and agents, invisible and unknown to us, can touch and smite in secret the springs of outward prosperity. (v) The time when decay began at the rising of the morning makes us think mournfully how human helps and comforts often wither at the very season when they are most needed. (vi) The utter loss of what had given such intense enjoyment warns us not to set our affections passionately upon anything which can be utterly lost, but to lift our supreme affection to things above the sphere of the "worm," and the "moth," beyond the reach of the "rust," and the "thief." (vii) The Divine "preparation" of the destroying insect to feed upon the plant which had been as divinely prepared, sheds some light amid the darkest mysteries of life, and brings a strong relief and assuagement to us amid the natural fears and doubts of our experience. Destruction is prepared by God as well as life; trouble as well as joy. And both are divinely ruled, with a view to the education and purification of human souls.
A. Raleigh, The Story of Jonah,p. 271.