What does this mean? How should we think about time?
Karl Barth suggests insight is gained by contrasting the Genesis account with the Babylonian myth, the Enuma elish.
Nor must we abstract from Gen. 1:14f. the fact that the history which it has in view, the content of the time which sun, moon and stars are created to measure, is not something indefinite, but the specific history of salvation which commences with the creation of light and receives its direction and purpose from the God of Israel. The relation of the creation of the heavenly bodies to chronology, and to that extent to history, is not unknown to the Babylonian myth, according to the fifth tablet of the Enuma elish.
But it is to be noted that in this case a metaphysical problem seems to be set in the forefront with the creation of the heavenly bodies. The sidereal world is supremely the abode of the great deities Anu, Enlil and Ea. And because the fundamental idea of Genesis is completely lacking, i.e., the separation of day from night as the action of sun and moon constituting time as day, all the emphasis falls, again with the precision of natural science, upon the phases of the moon dividing time into months- something which is not even mentioned in the present passage (note the complete absence of "month" in v. 14).
It is obvious that in the two accounts there is not merely a different chronology but a different conception of time. And it is to be noted that the specific biblical concept of time breaks through even where it is emphasised, as in Ps. 104:19, that God made the moon to divide the year. The day and time and history envisaged in Gen. 1:14f., and the reason why the luminaries shine from the firmament upon the earth to give signs and seasons and days and years, is made clear in v. 18, where day and night are again expressly interpreted as light and darkness.How does this effect the daily orientation and focus of humanity? Barth contrasts a preoccupation with this material world with a focus on the Creator and Covenant God.
The signs of the sky are of no value for the man who is merely concerned at random to orientate himself with the help of compass, clock or calendar, and to become the subject of any earthly history. They are of value only for the man whose day, season and history are to consist in his participation in the separation of light from darkness, because the God who separated light from darkness has created him in and as His own image, and because he was born and is called to be God's partner in this covenant.Karl Barth, Church Dogmatics III.1: The Doctrine of Creation, p. 163-4
Scientific time and time without reference to God are both uniform and everlasting. Biblical time is ultimately eschatalogical. Humans live in it, are accountable for how they live in it, and must face judgement and eternal realities.