Verses 40-51 do not introduce a new theme but return to the subject of verses 11-13 (see there). Good News Translation inserts a section heading here (“The Levites Take the Place of the First-Born Sons”), but we not recommend this (see the introductory comments on 3.1–4.49).

And the LORD said to Moses: See the comments on verse 11 and 1.1.

Number all the first-born males of the people of Israel: The Hebrew verb rendered Number is paqad, which is better translated “Enroll” (New Revised Standard Version) or “Record” (New Jewish Publication Society’s Tanakh; see the comments on 1.2).

From a month old and upward: See verse 15.

Taking their number by names does not make it clear whether this instruction concerns counting the number of Israelite names or listing their names. Revised English Bible clearly chooses the first sense, saying “and count the number of persons” (similarly De Nieuwe Bijbelvertaling). Other translations choose the second meaning; for example, New International Version and New Jewish Publication Society’s Tanakh say “and make a list of their names.” Given the census in this context, Revised English Bible is recommended as a model in languages where the choice has to be made. A similar model is “and count them individually.”

And you shall take the Levites for me … instead of all the first-born among the people of Israel: The LORD wants all the male Levites one month old and older for himself in place of all the firstborn males from the other Israelite tribes. New Revised Standard Version says “But you shall accept the Levites for me … as substitutes for all the firstborn among the Israelites.” Revised Standard Version and New Revised Standard Version render the Hebrew here more accurately than Good News Translation, which says “But in place of them I claim all the Levites as mine!”

I am the LORD is a reason for the sentence that it emphatically interrupts. The question is: what is this special placement emphasizing? It emphasizes that the LORD wants the male Levites for himself in place of the Israelites’ firstborn sons (so Good News Translation places “in place of them [the Israelites’ firstborn sons]” at the beginning of the sentence). New International Version moves I am the LORD to the end of the verse 41, which seems to be missing the point of the Hebrew word order here. New Jewish Publication Society’s Tanakh renders the first half of verse 41 as “and take the Levites for Me, the LORD, in place of every first-born among the Israelite people,” which also misses what the Hebrew is emphasizing. Both Revised Standard Version (with long dashes) and Good News Translation (with an exclamation mark) are helpful models to show this emphasis.

And the cattle of the Levites instead of all the firstlings among the cattle of the people of Israel: The LORD also wants all the domestic animals of the Levites in place of all the firstborn male animals from the other Israelite tribes (see verse 13). Cattle renders the same Hebrew word as “beast” in verse 13. As there, it refers to domestic animals here, so it is better rendered “livestock” (Good News Translation) in English to include not only cattle, but also sheep, goats, camels, and donkeys. Firstlings renders the same Hebrew word as first-born. In English it is more natural to say “first-born” (Good News Translation) here also.

Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .