Stony places - Where there was little earth, but where it was hard and rocky, so that the roots could not strike down into the earth for sufficient moisture to support the plant.
When the sun became hot they of course withered away. They sprang up the sooner because there was little earth to cover them.
Forthwith - Immediately. Not that they sprouted and grew any quicker or faster than the others, but they were not so long in reaching the surface. Having little root, they soon withered away.

Stony places - Where there was a thin surface of earth, and a rock at the bottom.

Some fell upon stony places,.... Such a place as the Jews call a barren, stony place, a place from whence, they say, they take stones, and , and which , "is not fit for sowing" (d); and such were those places and spots of ground, that some of these seeds fell upon; and design such hearers, in whom the natural hardness of their hearts continues, and who remain unbroken by the word, and are without any true sense of sin, and repentance for it.
Where they had not much earth, to cover them and take root in: this is expressive of such persons who have slight convictions of sin, and awakenings of the natural conscience; some little, light, and speculative notions of the word, in the understanding and judgment; some flashes of natural affection for it, and outward expressions of delight and pleasure in it; some show of grace, and a form of godliness, but no real heart work.
And forthwith they sprung up, because they had no deepness of earth; to strike their roots downwards: and through the reflection of the heat, upon the rocks and stones, they quickly broke through the thin surface of the earth over them, and appeared above ground before the usual time of the springing up of seed: which may not only denote the immediate reception of the word by these hearers, and their quick assent to it; but their sudden and hasty profession of it, without taking due time to consider the nature and importance thereof; and the seeming cheerfulness in which they did both receive and profess it; though it was only outward and hypocritical, and more on account of the manner of preaching it, than the word itself, and through a selfish principle in them; and did not arise from any real experience of the power of it on their souls, or true spiritual pleasure in it: nor could it be otherwise, since their stony hearts were not taken away, nor hearts of flesh given them; wherefore the word had no place in them, and made no real impression on them; they remained dead in trespasses and sins; the word was not the savour of life unto life unto them, or the Spirit that giveth life; they did not become living and lively stones; they continued as insensible as ever of their state and condition by nature, of the exceeding sinfulness of sin, of the danger they were in, and of their need of Christ, and salvation by him; they were as hard, and obdurate, and as inflexible, as ever, without any real contrition for sin, or meltings of soul through the influence of the love and grace of God; and as backward as ever to submit to the righteousness of Christ, being stout hearted, and far from it; and being no more cordially willing to be subject to the sceptre of his kingdom, or to serve him in righteousness and holiness, than they ever were; for the word falling upon them, made no change in them; their hearts were as hard as ever, notwithstanding the seeming and hasty reception of it; though they did not refuse to hearken to the word externally, did not put away the shoulder, or stop their ears, yet their hearts were still like an adamant stone: nothing but the mighty power of God, and his efficacious grace, can break the rocky heart in pieces; or give an heart of flesh, a sensible, soft, and flexible one, with which a man truly repents of sin, believes in Christ, and becomes subject to him.
(d) T. Bab. Erachin, fol. 32. 1. & Gloss. in ib. & Bava Bathra, fol. 156. 2. & Gloss. in ib.

Some fell upon stony places. Where the rocks that jut out of the hills into the plain had a very thin covering of earth. Much of Palestine is stony.