5.a. Selah is a scribal notation appearing in many psalms (71 times, plus 3 times in Habakkuk). The exact meaning is unsure, but it almost certainly indicated a pause in the reading of the text, despite ancient Jewish traditions that it meant “forever” or “everlasting.” The question of what the pause was for is much more difficult and has generated a plethora of answers (for convenient summaries and references, see Craigie, 76–77; A. A. Anderson, I, 48–49; M. D. Goulder, The Psalms of the Sons of Korah, JSOT SS 20 [Sheffield: JSOT Press, 1982], 102–4). The suggestions include bowing in prayer or prostration, probably with the recitation of liturgical sayings such as “forever,” “Yahweh is good,” or “for his loyal-love endures forever,” or a shout of “Hallelujah,” or some other appropriate expression. A refrain may have been sung or chanted, or the previous verse repeated, perhaps with a choir or the congregation joining the cantor. Goulder has argued for the meaning of a “cantillation” or “recitative,” in which the relevant section of a major tradition in Israel’s history would be recalled in prayer or in story (e.g., the cantillation of Josh 24 would be appropriate after Ps 44:8). We should remain open to the likelihood that the selah-pause was flexible, used in different ways in different psalms and on different occasions. In some psalms, the selah seems to mark off sections of the psalms into acceptable outlines; in others this does not seem to work well. The function of the selah as a poetic intensifier, at least in some cases, should be allowed. For the role of intensification in Hebrew poetry, see R. Alter, The Art of Biblical Poetry (New York: Basic Books, 1985), 62–84. Fairly frequently, the selah-pause seems to come just before a climactic statement or between such statements.
MARVIN TATE, PSALMS 51-100, VOLUME 20 (WORD BIBLICAL COMMENTARY), 33-34.