Let there be light

The phrase comes from the third verse of the Book of Genesis. In the King James Bible, it reads:
1.  In the beginning God created the heaven and the earth.
2. And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
3. And God said, Let there be light: and there was light.
4. And God saw the light, and it was good: and God divided the light from the darkness.