The differences between Levites and priests are complex and partly uncertain. It is not even certain that the author of Hebrews distinguished between priests and Levites, that is, between those Levites who descended from Levi through Aaron, and those who belonged to other branches of the Levi family.
Those descendants of Levi who are priests assumes that the writer did make this distinction, but it is made nowhere else in Hebrews, not even in verse 11 where one might expect it. These words may also be translated, perhaps better, as “the descendants of Levi, that is, the priests,” to contrast them with Melchizedek (verse 6), who was not a descendant of Levi at all.
Descendants is literally “sons.” The essential features are (a) one or more generations after Levi, including not only “sons” but “grandsons,” etc.; (b) male, thus not including female “descendants,” as the English word suggests; (c) adult, thus not including “children,” as in Luther 1984.
Who are priests is more precisely “who are given the office (or, function) of priests.” In order to avoid some of the difficulties involved in the rendering of those descendants of Levi who are priests, it may be possible to employ “those men who descended from Levi and who are priests” or “those men who look to Levi as the first of their tribe and who are priests.”
Revised Standard Version‘s “have a commandment in the law to take tithes” can be understood in two ways, and so can the Greek: (a) there is a law in the Torah (the Five Books of Moses) which assigns tithes to the priests; or (b) the Torah orders the priests to collect tithes. Meaning (a) is closer to the meaning of Numbers 18.21, except that in fact in this verse, all the Levites are given the right to claim tithes. Translators find it rather difficult to put this in common language. Knox has “are allowed by the provisions of the law,” Phillips “have the right to demand,” New American Bible “The law provides,” Barclay “possess with it [that is, the priestly office] an injunction which legally entitles them,” and Translator’s New Testament “are authorized to collect.” Meaning (b) is chosen by New English Bible “are commanded by the Law” and Jerusalem Bible “are obliged by the Law.” It may be possible to say “the Law commands” or “the words of the Law say.” But in many languages one cannot refer simply to “the Law,” even with capitalization. It may be necessary to state more specifically “the Law given to Moses,” “the laws that God gave to Moses,” or “… through Moses.” If such an expression is used, one may translate “according to the laws given to Moses it was necessary for the descendants of Levi to collect.”
The giving of “tenths” or “tithes” is a present-day custom in some cultures or groups but is unknown in others. In translations for groups to which the custom is strange, the translator should avoid any old-fashioned or specifically church-language word such as the English “tithe.” In such cases the translator may need to expand the text or to explain the custom in a glossary note.
Good News Translation‘s collect one tenth from the people could suggest the question “a tenth of what?” Die Bibel im heutigen Deutsch refers to a glossary note; Bijbel in Gewone Taal translates “tenths from the income of the people”; and Phillips puts “tenth” in quotation marks to identify it as a technical term. Quotation marks, however, cannot be read aloud. In speaking of “a tenth,” it is sometimes necessary to say more specifically “a tenth of what the people have earned” or “a tenth of what the people have acquired.” If a translation is being made for a society which makes little or no use of money, it is important not to rule out food or other goods.
The term collect may be rendered as “receive as offerings from.” It is important to avoid an expression which would suggest “taking away by force.”
Of Israel is implied. Knox‘s “God’s people” covers too wide an area of meaning, since Christians are not necessarily included.
“Brethren” (Revised Standard Version) has the wide meaning of “fellow Israelites.” Good News Translation adds their countrymen to make it clear that countrymen and not priests is the grammatical subject of are.
Descendants of Abraham is not literally “sons of Abraham,” as in descendants of Levi, but as in King James Version, “they come out of the loins of Abraham” (“loins” is a common way of speaking indirectly about the male reproductive organs). This is a statement which is developed in verse 10.
Instead of the Good News Translation word order, from the people of Israel, that, is from their own countrymen, it may be clearer to reverse the order, “from their own countrymen, that is, the people of Israel.” The final clause of verse 5 may then be rendered as “even though their fellow countrymen are also descended from Abraham” or “even though these people of their own nation look to Abraham as their ancestor.”
Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on The Letter of the Hebrews. (UBS Handbook Series). New York: UBS, 1983. For this and other handbooks for translators see here .