Jamieson, Fausset and Brown on Job 31:26

26. If I looked unto the sun (as an object of worship) because he shined; or to the moon because she walked, &c. Sabaism (from tsaba, "the heavenly hosts") was the earliest form of false worship. God is hence called in contradistinction, "Lord of Sabaoth." The sun, moon, and stars, the brightest objects in nature, and seen everywhere, were supposed to be visible representatives of the invisible God. They had no temples, but were worshipped on high places and roofs of houses (Eze 8:16; De 4:19; 2Ki 23:5, 11). The Hebrew here for "sun" is light. Probably light was worshipped as the emanation from God, before its embodiments, the sun, &c. This worship prevailed in Chaldea; wherefore Job's exemption from the idolatry of his neighbors was the more exemplary. Our "Sun-day," "Mon-day," or Moon-day, bear traces of Sabaism.