“The good land brings forth its vegetation by its Lord’s permission, whereas bad land produces only scant growth. Thus do We present the signs in varied forms for people who give thanks.”
He then mentions the differences among the lands upon which rain falls, saying: “The good land”—meaning land with good soil and composition—when rain falls upon it, “brings forth its vegetation,” for which it is suited, “by its Lord’s permission”; that is, by Allah’s will and volition. Causes do not independently bring things into existence; this only occurs when Allah permits it.
“Whereas bad land produces only scant growth”; that is, only poor vegetation devoid of benefit and blessing.
“Thus do We present the signs in varied forms for people who give thanks”; that is, We diversify and clarify them, set forth examples through them, and present them to people who thank Allah by acknowledging and affirming His blessings and using them in ways that please Him. They are the ones who benefit from the rulings and divine teachings that Allah has explained in His Book, because they regard them as among the greatest blessings to reach them from their Lord. They therefore receive them with a keen awareness of their need for them and with joy. They ponder and reflect upon them, and their meanings become clear to them in accordance with their receptiveness.
This is a parable of hearts when revelation—the source of life—descends upon them, just as rain is the source of life. When revelation reaches good hearts, they accept and learn it, then yield fruit according to the goodness of their roots and the soundness of their nature.
As for corrupt hearts, in which there is no good, revelation finds no receptive place when it reaches them. Rather, it finds them heedless and turning away, or actively opposing it. It is therefore like rain passing over salt flats, sand, and rocks without producing any effect. This resembles the words of Allah Most High: “He sends down water from the sky, and valleys flow according to their capacity; then the torrent bears swelling foam…” and the verses that follow.