And [mention, O Muḥammad], when your Lord said to the angels, "Indeed, I will make upon the earth a successive authority."1 They said, "Will You place upon it one who causes corruption therein and sheds blood, while we exalt You with praise and declare Your perfection?"2 He [Allāh] said, "Indeed, I know that which you do not know."
Translation: Saheeh International (English)
1 Khalīfah: successor, or generations of man, one following another.
2 An additional meaning is "...and we purify ourselves for You."
Allah tells His Prophet and humankind that He said to the angels that He would put humans on earth who will give birth to other humans, to inhabit it according to His laws. The angels asked their Lord, trying to understand, what the wisdom behind making the children of Adam guardians of the earth was, when they would ruin things in it, and kill in it, while the angels always do as He tells them, and recognise His greatness, praising Him and honouring His power and perfection. Allah replied to their question, saying that He knew the deep wisdom behind His creation of them, and behind making them guardians, and the angels did not.