What does Genesis 1:19 mean?

Genesis frames God's creation of all things using a poetic structure. This follows a strict pattern, where God speaks, creates, observes, and blesses His work. The day is then given a number. Verses 14 through 18 described the fourth day of creation, where God formed the sun, moon, and stars. Here, verse 19 closes out the description of the fourth creative day, referencing the concept of "evening and morning." In this time, Israel defined days from sunset to sunset, from evening through to morning, sunset to sunset.

God's creation of the sun, moon, and stars counters any belief that these are deities themselves. Many cultures, including ancient Egypt, worshipped the sun and moon as gods. Other religions, and modern astrology, believe that the position of these objects determines a person's fate. By making it clear that these are just pieces of God's creation, Genesis dispels any claims that there is supernatural power in the heavenly bodies.