What did the Holy One, blessed be He, do? He put forth His right hand and stretched forth the heavens, and He put forth His left hand and founded the earth, as it is said, "Yea, mine hand || hath laid the foundation of the earth, and my right hand hath spread out the heavens: when I called unto them, they stood up together" (Isa. 48:13). Both of them were created simultaneously, as it is said, "And the heavens and the earth were finished, and all their host" (Gen. 2:1).
And, indeed, were the heavens and the earth completed (so as not to require God's providence) for their continued existence and maintenance? Has it not been written concerning them, "Thus saith the Lord, The heaven is my throne, and the earth is my footstool" (Isa. 66:1)? But they were finished with reference to the original deed (of creation) and with reference to the work (of being created) and being called into existence. Therefore it is said, "And the heavens and the earth were finished" (Gen. 2:1).