Introduction. Psalm translations, from Hebrew, Greek (the Septuagint) and Latin (the Vulgate), were not unusal school exercises. Milton certainly performed such exercises (see his paraphrase on Psalm 114), but many of the translations published in the 1673 edition of Poems appear to have been done as much for devotional as for linguistic exercise. Certainly Milton also took pride in the breadth of metrical virtuosity displayed in these verse translations.
It is instructive to compare Milton's translation with those of the King James Version and the Geneva. Also interesting to compare is the Thomas Sternhold and John Hopkins version of 1562.
Italics indicate words that Milton has inserted to smooth out both the sense and the meter. According to Milton, "all but what is in a different Character, are the very words of the text, translated from the Original."
And. The 1673 edition has an inverted "n" — "aud".
Be Sether ragnam. The 1673 edition prints these Hebrew glosses in the margins. Their presence suggests that Milton was concerned with producing a fairly strict translation, one that would be widely accepted and used for common worship.
Meriba. The place where Israel is said to have complained to God about lack of food and drink; also called "Meribah." The word literally means "quarreling. See Exodus 17:7, Numbers 20:13, Numbers 20:24, Numbers 27:14, Deuteronomy 32:51, and Deuteronomy 33:8.
The shock. "A group of sheaves of grain placed upright and supporting each other in order to permit the drying and ripening of the grain before carrying" (OED2).