Answer: The work of creation is that wherein God did in the beginning, by the word of his power, make of nothing the world, and all things therein, for himself, within the space of six days, and all very good.₁

1. Genesis 1; Hebrews 11:3; Proverbs 16:4

For further study see:

1. WSC 9
2. John Calvin’s influence on this question.
3. Elder Gregory Moeck of First Orthodox Presbyterian, San Francisco explains WLC 15:
   
4. Elder Gregory Moeck of First Orthodox Presbyterian, San Francisco explains WLC 15 (part 2):