Let there be light

"Let there be light" is an English translation of the Hebrew (yehi 'or) found in Genesis 1:3 of the Torah, the first part of the Hebrew Bible. In Old Testament translations of the phrase, translations include the Greek phrase γενηθήτω φῶς (genēthḗtō phôs) and the Latin phrases fiat lux and lux sit.

Genesis 1:3
The phrase comes from the third verse of the Book of Genesis. In the King James Bible, it reads, in context:

Origin and etymology
In biblical Hebrew, the phrase (yəhî ’ôr) is made of two words. (yəhî) is the third-person masculine singular jussive form of "to exist" and (’ôr) means "light."

In the Koine Greek Septuagint the phrase is translated "καὶ εἶπεν ὁ Θεός γενηθήτω φῶς καὶ ἐγένετο φῶς" — kaì eîpen ho Theós genēthḗtō phôs kaì egéneto phôs. Γενηθήτω is the imperative form of γίγνομαι, "to come into being."

The original Latinization of the Greek translation used in the Vetus Latina was lux sit ("light – let it exist" or "let light exist"), which has been used occasionally, although there is debate as to its accuracy.

In the Latin Vulgate Bible, the Hebrew phrase is translated in Latin as fiat lux. In context, the translation is "dixitque Deus fiat lux et facta est lux" ("And said God let there be light, and there was light"). Literally, fiat lux would be translated as "let light be made" (fiat is the third person singular present passive subjunctive form of the verb facio, meaning "to do" or "to make"). The Douay–Rheims Bible translates the phrase, from the Vulgate, as "Be light made. And light was made."