I'm studying Hebrews, using the new NRSVue, and am not sure with what to do with their Psalm 110 "alternative" interpretation. The text of v.4 reads “You are a priest forever according to the order of Melchizedek.” But then there’s a footnote: “Or ‘forever, a rightful king by my edict.’” The traditional translation is, as I see it, is Jesus-directed, with a less political feel. Are they leading us beyond what is written?

Psalm 110:4, in the New Revised Standard Version Updated Edition (or NRSVue) has Melchizedek, but you’re right, the footnote casts some doubt on this reading. This alternative translation feels less Messianic and less Christian. And it would mean that the New Testament writer of Hebrews (5:6, 10; 6:20; 7:1, 10-11, 15, 17) was confused. This I doubt. The Greek translators (LXX) followed the Hebrew (MT, or Masoretic Text), so the OT of most early Christians (the LXX) supports the traditional reading.

“In the manner of a king of righteousness” is a possible translation. If we break Melchizedek into its two constituent parts, we get king and right[eousness]. The footnoted reading “by my edict” takes ‘l-dvr as “by,” and it is true that the phrase can mean “because of” (as in Ecc 3:18; 7:14; 8:2). Divrāh = manner; dāvār = word (perhaps edict). Yet in Ps 110 the usage seems to be modal, not causal (as Leslie C. Allen observes [WBC 21, 2002 (p.111]) —“according to the way of,” “on the model of”—not “by” or because of.”