Q. 15. What is the work of creation?
A. 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.
I think the Scriptures speak for themselves here.
Genesis 1:1 In the beginning God created the heaven and the earth.
Joh 1:1 In the beginning was the Word, and the Word was with God, and the Word was God. Joh 1:2 The same was in the beginning with God. Joh 1:3 All things were made by him; and without him was not any thing made that was made.
Hebrews 11:3 Through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear.
Proverbs 16:4 The LORD hath made all things for himself: yea, even the wicked for the day of evil.
Revelation 4:11 Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created.