CCC 338 Nothing exists that does not owe its existence to God the Creator. The world began when God’s word drew it out of nothingness; all existent beings, all of nature, and all human history are rooted in this primordial event, the very genesis by which the world was constituted and time begun.1
1 Cf. St. Augustine, De Genesi adv. Man 1, 2, 4: PL 34, 175.