Job 26:10 --
"He has inscribed a circle on the face of the waters at the boundary between light and darkness." NSV
Proverbs 8:27 --
"When He established the heavens, I was there, When He inscribed a circle on the face of the deep," NASB
Isaiah 40:22 --
"He sits enthroned above the circle of the earth, and its people are like grasshoppers. He stretches out the heavens like a canopy, and spreads them out like a tent to live in" NIV
None of those statements describe the earth as spherical and instead fit with the flat-earth cosmology that was typical for the ANE and in other Jewish writings.
The statements in Job 26:10 (choq-chog `al-p e nê mayim "he inscribed a circle on the surface of the waters") and Proverbs 8:27 (b e chûqô chûg `al-p e nê tehôm "when he inscribed a circle on the surface of the deep") clearly refer to the drawing of a circle on a 2D surface. According to Job, this was to "mark a boundary between light and darkness "; the idea is that of the horizon which is the limit beyond which the sun passes from view. In ANE cosmology the sun then passed through the underworld at night so that it would rise the next morning in the east. Job 26 is pretty chock full with mythological imagery, incidentally, with its references to the Rephaim of the underworld (v. 5-6), the pillars of heaven (v. 11), and the Chaoskampf motif of God's battle against the sea dragon (v. 12-13), with even the idea of churning the sea as roiling the dragon (something that sounds straight out of the Enuma Elish). The inscribing of the circle on the deep itself might reflect the common idea that the earth was encircled by an ocean. Here is the "circle of the earth", with that world-circling ocean, as envisioned by the Babylonians:
Isaiah 40:22 even more distinctly evokes the image of ANE cosmology: the earth is a flat disk with the heavens streched over it like a tent, and with God at the apex looking down at the tiny humans from such a height. The tent metaphor is used elsewhere. In Psalm 19, we read that "in the heavens God has pitched a tent for the sun. It is like a bridegroom coming out of his chamber, like a champion rejoicing to run his course. It rises at one end of the heavens and makes its circuit to the other" (v. 4-6). Psalm 104 similarly says that Yahweh "set the earth on its foundations" and "stretches out the heavens like a tent, and lays the beams of his upper chambers on their waters" (v. 2-5).
In Mesopotamia, the Gilgamesh Epic (Tablets IX-X) has the hero journey to Mount Mashu at the ends of the world to follow the "path of the sun" through the realm of total darkness in the underworld. Gilgamesh enters the tunnel underneath the mountain and passes through the underworld, barely making his exit before the sun catches up with him. He then exits and finds a beautiful garden of jeweled trees. Egyptian religion had two notions of the night-time journey. The older one (dating back to the Old Kingdom) pictures a flat earth in a reclining male god Geb with the arched firmament as an arched Nut extending over him. The sun god Re journeys to the east by entering through Nut's body during the night, where it is unseen by those on the earth. But another tradition (also quite old) is that Re battles with the demon Apophis during the night after the sun sinks below the horizon. Apophis lay at the base of Mount Bakhu at the western edge of the earth but he could also attack Re in the east (thus some texts refer to Apophis as the "world encircler"). Re must thus travel on his bark with a complete entourage to protect him from harm. Similar ideas can be found in the Canaanite texts of Ugarit. The sun goddess Shapsh journeys to the underworld at night on a bark piloted by Kothar who protects her from Arsh and the dragon (just as Seth defends Re's bark from attack by Apophis); Shapsh rules over the Rephaim of the underworld and it is she who takes the dead to the underworld at night (KTU 1.6 vi 45-53), just as she is the one who helps Anat bring Baal out of the underworld. In later Jewish literature, the patriarch Enoch makes a journey through the underworld in a manner very much like Gilgamesh in the Book of Watchers (1 Enoch 17-24, especially). The Book of Luminaries also has a flat-earth cosmology that construes the sun as rising and setting through certain gates (364 in number) at the edge of the world. In one later rabbinical text, the sun makes its nocturnal journey not through the underworld (as in Babylonian, Egyptian, Canaanite cosmology) but in heaven itself above the firmament: "The learned of Israel say that the sun moves by day beneath the firmament and by night above the firmament, whereas the learned of the nations say that the sun moves by day beneath the firmament and by night beneath the earth" (Baraita Pesahim 94b).
Hellenistic philosophers and scientists understood that the earth was spherical, but it took a long time for popular notions to change. Similarly, Greco-Roman scientists were able to predict eclipses but still people popularly thought of eclipses as unexpected omens. It is not until the third and fourth century church fathers (Lactantius, Augustine, etc.) when the spherical cosmology was accepted as fact.
