وَاِنْ مِّنْ شَيْءٍ اِلَّا عِنْدَنَا خَزَاۤىِٕنُهٗ وَمَا نُنَزِّلُهٗٓ اِلَّا بِقَدَرٍ مَّعْلُوْمٍ ( الحجر: ٢١ )
Wa im min shai'in illaa 'indanaa khazaaa 'inuhoo wa maa nunazziluhooo illaa biqadarim ma'loom (al-Ḥijr 15:21)
And there is not a thing but that with Us are its depositories, and We do not send it down except according to a known [i.e., specified] measure. (Al-Hijr  : 21)
1 Mufti Taqi Usmani
We have treasures of every thing, but We send it down only in a determined quantity.