"It is He Who hath made you (His) agents, inheritors of the earth: He hath raised you in ranks, some above others: that He may try you in the gifts He hath given you: for thy Lord is quick in punishment: yet He is indeed Oft-forgiving, Most Merciful" (Al-An'âm 6: 165)
Sayings of Prophet Muhammad PBUH about the seven skies from Sahih Bukhari and (Muslim)
“Allah created on the same day when He created the skies and the earth, one hundred mercies,
each mercy is coextensive with the space between the sky and the earth,
and He endowed one part to the earth, and it is because of this part
that the mother shows affection to her child, and that the beasts and
birds show kindness to one another, and when there would be the day of
resurrection, Allah would make full (use) with this mercy”.