לְאֹתֹת֙ וּלְמֹ֣ועֲדִ֔ים וּלְיָמִ֖ים וְשָׁנִֽים
Signs, seasons, days and years
Having made the earth habitable, God made the heavens useful. Aside from distinguishing day from night, the "clock" became a calendar.
The word "signs" is the Hebrew אוֹת (ōth). As with the translation, the word indicates a signal. Signs identify the true state of things. The lights in the sky are used to confirm the message of the creator.
A season (מוֹעֵד mo`ed) is an appointed place or time. Affixing the prefix "m" to the root verb יָעַד ( yâʻad) forms the noun. By watching the sky regular meetings and activities can be scheduled.
The orbs and points of light also make it possible to observe special days. These include the first day of the month and year (Heb: שָׁנָה, shaneh).
The year is marked when the sky returns to its original appearance. The word שָׁנָה is taken from the verb form shanah, the same root for the number two.
The place of the earth among the heavenly bodies was designed to allow a clear view of what has been set in place. As the Psalmist would write "The heavens declare the glory of God" (Ps. 19:1).