The ancients needed no clocks to tell them when they passed the boundary line between day and night—sunrise began the day and sunset ushered in the night. Therefore a day in the calendar is measured by one complete rotation of the earth on its axis, including a day and a night. Each full day ran evening-morning, dark-light, night-day (Leviticus ; 22:6, 7; Mark , 32).
Also certain other ancient peoples, like the Babylonians, began their day at sunset, although the Egyptians counted from sunrise.
Yet the Sabbath, given in the beginning by the God of nature, definitely marked off by the manna, even before the law at Sinai, is identified in the New Testament (Genesis 2:1-3; Exodus 16:4, 5, 22-26; 20:8-11; Luke to 24:1); since then we can count the weeks back into the past with certainty from known dates.
The three natural motions that measure our time are incommensurable, that is, do not “come out even.” While the earth is making one revolution around the sun, the moon revolves around the earth 12 times and about a third of a circuit over, and the earth turns on its own axis 365 times plus a little less than a fourth of a turn.
As we, on any given spot on this spinning globe, are carried eastward, out of the sunlight and into the shadow, we say that the sun is setting in the west.As our local spot approaches the point directly opposite the sun, that fiery orb appears to rise higher in our sky until it is on our meridian at noon.Then it appears to decline as we move farther around the sunlit side, and we complete one circuit as we again reach the sunset line—the edge of the shadow. And so it was, for in His time an hour meant one twelfth of the interval—varying with the seasons—between sunrise and sunset. A period marked off by five days, or any number of days, cannot disregard the intervening nights.There are some points left open for personal opinion as to the exact dating, and different writers among us have at various times used differing dates.This is not to say that historical dates do not help us sometimes in our search for deeper spiritual truth, or that those few connected with exact prophetic periods are unimportant; but prophetic landmarks are well established, and other historical dates are rarely questions of theological importance.The ancient lunar month did not begin at the astronomical new moon, when that body stands between the earth and the sun—with its unlighted side toward us, and hence invisible—but one or more days later, with the appearance of the new crescent.Now, however, most of the world uses artificial calendar months that disregard the moon.The Year Measured by the Sun.—As our spinning earth, circled continuously by the moon, traverses its vast course around the sun, it makes the circuit of the four seasonal landmarks—the summer and winter solstices and the spring and autumnal equinoxes—to complete what we call a year.These points do not mark off the year as visibly as the moon does the lunar month, yet even relatively primitive peoples can recognize them by repeated observation of the shadows cast by the sun at rising, setting, and noon throughout the year.Many supposed difficulties have been cleared up by increasing knowledge of ancient chronology.Although we cannot expect all authorities to agree in their interpretation of the incomplete facts of ancient times, we can confidently expect future research to strengthen the Bible record.