Radak: We serve Him because He made the land. It says b'Kocho regarding the land, because the spheres [on which the Heavenly bodies rotate] constantly go around constantly, without ceasing. The strength [to rotate them] is from Him. Via that strength, the land stands suspended between them. It does not move this way or that, even a hair's breadth - "Toleh Eretz Al Belimah" (Iyov 26:7). A person does not know on what it is suspended. A Chacham contemplates that from the power of the rotation, it stands between them without any support. Even though there is another reason, that its nature is to stand ¹ in the middle. Even though it is heavy, Hashem gave to it this nature; everything is from His power.

Malbim: The present tense is used, for Hashem constantly prepares and renews the creation via His constant Hashgachah.

Radak, Malbim: It is the settled places of the land. Hashem prepared them with His Chachmah, with all needs. Radak - it has (a) flowing rivers and streams, which are essential for civilization; (b) all vegetation and Peros needed for man and animals grow there, and (c) all benefits. He did all with Chachmah.

Rashi: He stretched out. Radak - He stretched it like a tent to live under it - "va'Yimtachem ka'Ohel Lashaves" (Yeshayah 40:22). It is like a half-sphere. We see only a half-sphere in Shamayim above the Aretz, but we infer that there is another half-sphere [below the land], for [Shamayim] is a sphere. The stretching of Shamayim, and its quick motion from east to west and from west to east was all done with understanding that one cannot fathom.