The precise and consistent division of time into hours, minutes, and seconds is a feature of modern life first made possible by the widespread use of mechanical clocks in the late Middle Ages. Biblical texts reflect an earlier situation in which timekeeping was primarily a matter of celestial observation. NT references to “hours” fall into two broad categories: first, timekeeping by means of numbered hours; and second, the use of the word “hour” in the sense of “moment,” a short, indefinite period of time (e.g., Matt. 8:13; John 16:2), as the hour was the basic unit of measurable time (see Rev. 9:15).

Jesus observed that the day was divided into twelve hours (John 11:9). Jesus was crucified at the third hour (9 a.m.); it was dark from the sixth hour (noon) until the ninth hour (3 p.m.), at which point Jesus died (Matt. 27:45–46; Mark 15:25, 33; Luke 23:44; John 19:14). In one parable, a landowner hired workers at the third, sixth, ninth, and eleventh hours (Matt. 20:3–12). The book of Acts also reports events occurring at the third, sixth, and ninth hours (Acts 2:15; 3:1; 10:3, 9). Such passages suggest that actual reckoning was often less precise even than the twelve-hour scheme permitted, and that the day was more roughly divided into four parts of three hours each. The Gospel of John provides the most precise time indications, mentioning the tenth hour (4 p.m. [John 1:39]) and the seventh hour (1 p.m. [John 4:52]). One text names an “hour of dinner” (Luke 14:17; see also 22:14), and another indicates that the ninth hour (3 p.m.) was an “hour of prayer” (Acts 3:1; see also 10:30).

The night was divided into three or four “watches,” of which the NT mentions the second, third (Luke 12:38), and fourth (Matt. 14:25; Mark 6:48). The OT mentions nocturnal watches (Pss. 63:6; 90:4; 119:148; Lam. 2:19), including in military contexts (Exod. 14:24; Judg. 7:19; 1 Sam. 11:11), from which the term with the sense of standing guard is derived. The OT watches are not numbered, but are referred to as “middle” or “last.” The system of watches did not preclude the counting of hours during the night, as in Acts 23:23, which refers to the third hour of the night (9 p.m.).

In addition to the numbered hours of the day, the hour is also used to measure the passage of time, as in Acts 19:34, where a crowd riots for two hours (see also Matt. 26:40; Luke 22:59; Acts 5:7; Rev. 17:12). One text refers to a half-hour period (Rev. 8:1).

Numerous texts refer to hours of future trial (Matt. 10:19; Rev. 3:10), including an eschatological or “last hour” (e.g., Mark 13:32; 1 John 2:18). The suffering and death of Jesus is also referred to as his “hour” (e.g., Mark 14:35; 14:41; John 12:23, 27).