Its meaning is that, even if falsehood rises for a time, it will surely vanish. It was also said that “as scum” means scattered apart. One says that the wind has cast the clouds away when it disperses and carries them off.

“And as for that which benefits people”—that is, water and metals: gold, silver, brass, and copper—“it remains in the earth,” meaning, it endures and does not disappear.

“Thus Allah sets forth parables.” Allah, Most High, has made this a parable for truth and falsehood: falsehood is like foam, which goes away and is lost, whereas truth is like water and metal, remaining in the hearts. It was also said that this is a consolation for the believers: the affair of the idolaters is like foam, which appears to be something in outward form but has no reality; whereas the affair of the believers is like water settled in its place, possessing endurance and firmness.

“For those who have responded to their Lord is the best reward. But those who did not respond to Him—if they had all that is in the earth, and the like of it with it, they would offer it as ransom. Those will have the worst reckoning, and their refuge is Hell—an evil resting place.” (18)