Psalm 89/Notes/Lexical.v. 16.80987

• The noun תּרוּעָה describes a "loud sound... used to express an emotion or to communicate something to a community" (SDBH). It could simply be an expression of joyful emotion (cf. the following verse יגילון, but the fact that it is the object of the verb "know" (ידע) suggests that it has a communicative function; it is a "signal" (cf. Symmachus: σημασίαν, "the giving a signal or command" [LSJ]), the significance of which is "known" only to YHWH's people. The תּרוּעָה probably signals "victory" (Jerome, trans. Risse) or, more specifically, YHWH's royal presence on the battlefield with his people to give them victory. This interpretation makes sense in the context: the parallel line mentions the light of YHWH's presence (v. 16b), and the following lines use military language (vv. 18-19). This interpretation also coheres well with the use of תּרוּעָה outside of this psalm. In 1 Sam 4:5-6, the people shout to signal YHWH's presence with them in battle: "As soon as the ark of the covenant of the LORD came into the camp, all Israel gave a mighty shout (תְּרוּעָה), so that the earth resounded. And when the Philistines heard the noise of the shouting (הַתְּרוּעָה), they said, 'What does this great shouting (הַתְּרוּעָה) in the camp of the Hebrews mean?'" In 1 Sam 4, only YHWH's people understand the significance of the "shout;" the Philistines do not understand. Thus, in Ps 89, "those who know the signal" is a way of referring to YHWH's people, who experience his presence with them in battle.
• Shouting (or blowing a horn) to signal YHWH's presence is probably related to the practicing of hailing a king (cf. 1 Sam 10:24; Num 23:21; cf. Gesenius 2013, 1458: "Königsjubel;" so Ibn Ezra, Radak). Thus, the word is used "especially in contexts where Yahweh is acclaimed as king" (TDOT) (cf. Num 23:21; Pss 47:2, 6; 95:1; 98:4; 150:5). YHWH's kingship is clear in this context as well; the previous verse of Ps 89 mentioned YHWH's "throne" (v. 15).