Genesis 1:18

The English word can sound that way, since “firmament” comes through a Latin word for something firm. The Hebrew word, râqîyaʻ, comes from a root meaning to stamp or to spread out, and it means an expanse, the wide arch of the sky that you see overhead. The BSB reads expanse. God made it on the second day to divide the waters (Genesis 1:6–8) and called it Heaven (Genesis 1:8), and on the fifth day the birds fly “in the open firmament of heaven” (Genesis 1:20), which would be a strange thing to say of a hard shell. So the word takes in everything above us, from the air to the farthest stars, and the sun is in it in the sense anyone can see by looking up. Genesis describes the sky the way a person standing on the earth sees it, and it gives no teaching about a solid shell or about distances.

To divide, bâdal, means to separate or set apart. The rising and setting of the lights draws the line between day and night for everyone who lives on the earth. Day and night were already there, because on the first day God divided the light from the darkness himself and named them Day and Night (Genesis 1:4, 1:5). Now he appoints the lights to carry on that dividing. The day and night stay as they were, and from now on they have a sun and moon to mark them, every day that follows.

A sign, ʼôwth, is a signal, mark or token, something that points beyond itself. The lights are marks anyone can read, telling you the hour and the time of year, and travellers and sailors have long found their way by the stars. God has also used the sky for signs of particular things. A star announced the birth of the King of the Jews (Matthew 2:2), and Jesus said there would be signs in the sun, moon and stars before his return (Luke 21:25; compare Joel 2:31).

The lights are signs of the time and, when God chooses, of what he is doing, and reading a person’s future or character from them is something else entirely, which Scripture forbids. God’s law forbids divination (Deuteronomy 18:10), Isaiah mocks the stargazers who were powerless to save Babylon (Isaiah 47:13), and the LORD tells his people, “be not dismayed at the signs of heaven; for the heathen are dismayed at them” (Jeremiah 10:2).

The word for seasons, môwʻêd, means an appointed or fixed time, and it often means a festival. It is the word used of the LORD’s feasts in Leviticus 23:2. So “seasons” here takes in more than spring and summer, although the turning of the year is part of the picture: “thou hast made summer and winter” (Psalm 74:17). Israel’s feasts were given long after these words were spoken, and they would be dated by month and day (Leviticus 23:5), with the new moons kept as well (Numbers 28:11). As the psalm says, “He appointed the moon for seasons” (Psalm 104:19). From the fourth day, then, the lights in the sky were ready to keep time for the worship of God’s people.

In the sun and moon God gave us a clock and a calendar that cost nothing, can be seen from anywhere and always keep good time. The sun gives the day and the year, and the moon gives the month, so people everywhere can count their time without any help from one another. The whole round of life on the earth runs by them. In the daylight people go out to their work until the evening (Psalm 104:23), and in the dark “all the beasts of the forest do creep forth” (Psalm 104:20). The sun’s light brings warmth and makes things grow, and in his blessing of Joseph Moses speaks of “the precious fruits brought forth by the sun” (Deuteronomy 33:14).

Every sunrise is also a small, steady proof that God keeps what he sets in place. God himself points to this when he tells Jeremiah that his covenant with day and night stands firm, and he sets his promises to his people beside it (Jeremiah 33:20, 33:21, 33:25–26). “The heavens declare the glory of God” (Psalm 19:1), and what he has made shows his power so clearly that people are left without excuse (Romans 1:20).

The sun and moon come first because they have charge over day and night and matter most to life on the earth, as seen from the ground. The stars are as great to God as ever. He counts them and gives each one its name (Psalm 147:4, Isaiah 40:26), and making all of them takes only a short clause to tell. The verse leaves numbers and distances unsaid, but it claims every star for God, however many there are and however far away. Scripture elsewhere says that the host of heaven is beyond counting (Jeremiah 33:22; compare Genesis 15:5). The more we learn of how vast the heavens are, the larger this short clause becomes.

The moon shines by reflecting the sun, and the verse fits with that. It calls the moon a light because it gives light on the earth at night, which it does. We talk the same way today when we say that the moon lit up the road. The verse describes what the moon does for us and leaves aside where its light comes from.

The plants had light from the start, because God made light on the first day, and evening and morning had already come three times (Genesis 1:3, 1:5, 1:13). Genesis leaves the reason for the order untold, but the order itself teaches something. Green things were growing before any sun shone, so life on the earth is owed to the word of God, who made the sun too. The lights then arrive just before the creatures who will live by them, which are made on the fifth and sixth days.

What gave the first light, we are never told, and the God who made the sun is able to give light apart from it. Scripture can name the two side by side: “thou hast prepared the light and the sun” (Psalm 74:16). The Bible’s last chapter describes a city where “they need no candle, neither light of the sun; for the Lord God giveth them light” (Revelation 22:5).

Believers differ here. The plain reading is that they were made on this day, because God says “Let there be lights” and then makes them, and many take it that until then God provided light directly, or by some means he has chosen to leave undescribed. Others hold that the sun and moon were part of the heaven God created “in the beginning” (Genesis 1:1), and that the fourth day tells of their being appointed and made to serve the earth. They point to how broad a word ʻâsâh is. Read in order, “God set them” in verse 17 continues the same day’s work: verse 16 says God made the lights, and verse 17 says where he put them and what for.

Believers who read the days as ordinary days often answer that God made the stars with their light already reaching the earth, because verses 15 and 17 say they were there to give light upon the earth. In the same way, they note, God made fruit trees already yielding fruit and man ready to fill the earth (Genesis 1:11, 1:27, 1:28). Some of them add that how light and time behave across such distances may be more than we fully understand. Those who read the days as long ages, or who place the making of the stars in Genesis 1:1, find the distances and the days in easy agreement. On any of these readings, the stars are there because God made them, and every distance is within his reach.

Hebrew has ordinary names for them, shemesh and yareakh, yet verse 16 calls them the greater light and the lesser light, by what they do. The likeliest reason, though one we have to infer, is that people were tempted to worship them. A lamp is hard to bow down to. Calling them lights makes plain that they are things and that God made them.

Verse 18 finishes the sentence begun in verse 17. God set the lights in the sky “to rule over the day and over the night, and to divide the light from the darkness”. The verb for rule, mâshal, means to have dominion or to govern, and like the noun in verse 16 it is used as a picture. The sun and moon rule the way a clock rules a household, by setting the times that everyone else keeps. Daylight comes when the sun comes up and ends when it goes down, and the moon is the great light of the night sky. Jeremiah calls this God’s own order when he says the LORD “giveth the sun for a light by day, and the ordinances of the moon and of the stars for a light by night” (Jeremiah 31:35). They keep at it day after day, as a psalm says of the sun’s course: “there is nothing hid from the heat thereof” (Psalm 19:6).

Their rule is a post under God, the way a steward holds his post under his master, and the LORD’s own kingdom rules over all (Psalm 103:19). The lights hold their place because he assigned it to them, and they carry out his will in it.

The words “to divide the light from the darkness” repeat what God himself did on the first day, when “God divided the light from the darkness” (Genesis 1:4), and the task he announced in verse 14. So what God commanded is what was done, and the work he began on the first day goes on through the lights he has appointed. The word for light here is ʼôwr, light itself, the word used of the first day’s light, and the darkness is chôshek, the dark.

The rule in this verse belongs to the day and the night. Man is given his own dominion over the living creatures in Genesis 1:26 and 1:28. Scripture does elsewhere compare a just ruler to the light of the morning when the sun rises (2 Samuel 23:3, 23:4), and that is a fair picture of good rule, but it belongs to a separate teaching.

Believers differ over how long these days were, and the fourth day is where the question comes up most naturally, because it is the day the sun appears. The word for day, yôwm, can mean the warm hours of daylight, a full day from one sunset to the next, or a wider span of time set by the words around it.

• Ordinary days. Many hold that the days were ordinary days of about 24 hours, because each has an evening and a morning and a number, and because God’s six days of work are the pattern for Israel’s working week and Sabbath (Exodus 20:11). They point out that the same closing words end the days before the sun and the days after it, which marks the fourth day as the same kind of day as the first three.
• Longer periods, or a framework. Others read the days as longer periods, or as a God-given way of ordering the account. They note that a thousand years are as a day to the Lord (Psalm 90:4, 2 Peter 3:8), and that the first three days came before there was a sun to measure them, so for them a day is set by the light and darkness God made on the first day.

The question is taken up more fully at Genesis 1:5, where God names Day and Night before the sun is made. On every reading, God made the lights and gave them their work, just as these verses say.

The chapter’s own details show a pattern. On the first day God makes light, and on the fourth he makes lights. On the second he makes the sky and divides the waters, and on the fifth he fills the waters with creatures and the sky with birds (Genesis 1:20). On the third he brings out the land and the plants, and on the sixth he makes the animals and man to live there and eat what grows (Genesis 1:24, 1:29). The earth began “without form, and void” (Genesis 1:2), and these six days give it form and then fill it. Genesis leaves the pattern for us to see, and seeing it sits well with the order in which the days are told.