Genesis 1:1

In the beginning God created the heaven and the earth.

This verse has always fascinated me. What power, what authority it shows! Nothing existed, but when God commanded, things that didn't even exist had to obey Him: the heaven and the earth came into being. A few years ago, I learned a little bit about some of the creation myths from other ancient cultures and how Genesis 1 is a response to them. Most of the ancient civilizations' stories of creation start out with the heaven and earth already existing, and gods and goddesses somehow are borne out of the already existing matter of the universe. Not so with the true God: He caused matter to exist. His existence did not come about spontaneously out of what existed before Him. No, everything that exists outside of Him comes to be as a direct result of His will and power.

From the Catechism of the Catholic Church:
279 "In the beginning God created the heavens and the earth." Holy Scripture begins with these solemn words. The profession of faith takes them up when it confesses that God the Father almighty is "Creator of heaven and earth" (Apostles' Creed), "of all that is, seen and unseen" (Nicene Creed).

280 Creation is the foundation of "all God's saving plans," the "beginning of the history of salvation" that culminates in Christ. Conversely, the mystery of Christ casts conclusive light on the mystery of creation and reveals the end for which "in the beginning God created the heavens and the earth": from the beginning, God envisaged the glory of the new creation in Christ.

290 "In the beginning God created the heavens and the earth": three things are affirmed in these first words of Scripture: the eternal God gave a beginning to all that exists outside of himself; he alone is Creator (the verb "create"—Hebrew bara—always has God for its subject). The totality of what exists (expressed by the formula "the heavens and the earth") depends on the One who gives it being.

See also:
Haydock's Bible Commentary, 1859 edition