A. Yusuf Ali:Translation:
And those who had envied his position the day before
began to say on the morrow: "Ah! it is indeed Allah
Who enlarges the provision 3412 or restricts it, to
any of His servants He pleases! had it not been that
Allah was gracious to us, He could have caused the
earth to swallow us up! Ah! those who reject Allah will
assuredly never prosper."

3412 Provision or Sustenance, both literally and figuratively: wealth and material things in life as well as the things that sustain our higher and spiritual faculties. The rabble, that admired Qarun's wealth when he was in worldly prosperity, now sees the other side of the question and understands that there are other gifts more precious and desirable, and that these may actually be withheld from men who enjoy wealth and worldly prosperity. In fact it is false prosperity, or no prosperity in the real sense of the word, which is without spiritual well-being (Cf. 29:17, 30:37, and 39:52).