Verse 7 begins with a repetition, “Only be strong and very courageous.” The Greek Old Testament omits “very,” probably because it does not appear in the parallel at verse 6.
The command is now followed by the equally strong command, make sure that you obey the whole Law that my servant Moses gave you. The Greek Old Testament omits the whole Law and has only “obey what my servant Moses commanded you.” It is suspected that the whole Law is a later addition to the Hebrew text (see Bright, Soggin), particularly since in the following, “do not depart from it,” the pronoun “it” in Hebrew is masculine, not feminine as it should be if referring to the Hebrew feminine word for “law.” But the phrase is in the Hebrew text and should be represented in translation. Its omission by the Greek Old Testament was perhaps an attempt to ease the problem of the Hebrew text. This “whole Law” probably refers to part, if not all, of the book of (Deuteronomy see verse 8 “this book of the Law”).
In Hebrew make sure that you obey the whole Law is literally “to obey to do according to the whole Law.” The structure “to obey to do” reflects the fondness of Hebrew for the use of parallel expressions. Actually both verbs, “obey” and “do,” carry the same force in Hebrew, and the combination of the two verbs serves to make the command more emphatic. This is the basis for Good News Translation make sure that you obey; one may also translate “see to it that you obey,” or merely “obey,” if the use of a single verb in the receptor language is more emphatic than the use of two verbs. The Hebrew structure “according to the whole Law” has the function of identifying “the whole Law” as the object of the two verbs. One may translate “everything that is taught in my (that is, the LORD’s) Law” or “everything that my Law teaches you to do.”
The imperative obey the whole Law may be rendered either “faithfully obey the (or, my) Law” or “completely obey my Law” by shifting the modifier “whole” from the noun “Law” to the verb “obey.”
If Joshua faithfully follows everything the Law requires, he will succeed in all he undertakes. Do not neglect any part of it (literally “do not turn from it to the right or the left”) is a way of saying not to deviate, but to remain faithful in following what is required. Wherever you go refers not simply to movement or travel as such but to all of one’s activities; so Jerusalem Bible “in all you do.” Succeed translates a verb meaning “to prosper, be successful”; the clause may be rendered, “then you will succeed in everything that you undertake.”
In Hebrew the second person singular in verses 7-9 seems to have Joshua as the one to whom the Lord is talking; it very well may be, however, that the Lord is really speaking to Israel (so Bright). The demands and promises are addressed to Israel as a whole and not just to Joshua personally. But most translations apparently utilize the singular form, and this would seem to be the best course to follow.
Quoted with permission from Bratcher, Robert G. and Newman, Barclay M. A Handbook on Joshua. (UBS Helps for Translators). New York: UBS, 1983. For this and other handbooks for translators see here .