You shall set apart is literally “you will cause to pass through.” This suggests the idea of causing something to pass through fire, or to sacrifice, as in 2Kgs 16.3. So Good News Translation has “you must offer.” To the LORD, however, probably gives it the meaning of “offer,” or “surrender” (Jerusalem Bible, Translator’s Old Testament), or “set apart” (New Jewish Publication Society’s Tanakh), or just “give” (Contemporary English Version). (Fox has “transfer.”) All that first opens the womb is discussed at verse 2.

All the firstlings is literally “all firstborn, offspring.” Of your cattle that are males is literally “animals that will be to you males.” Good News Translation simply has “Every first-born male of your animals.” The word used here includes all animals, domesticated and wild, but “your animals” includes only domesticated animals, or “livestock” (New Revised Standard Version). Shall be the LORD‘s is just one word, “to [or, for] Yahweh,” meaning “belongs to the LORD.” In languages that must clearly distinguish between the firstborn human males and those of domesticated animals, this verse may be rendered as follows:

• You [plural] must offer [or, give] every firstborn son to the LORD, and also every firstborn male from your domesticated animals. All these belong to the LORD.

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .