12 Ps 18:4 reads “ropes,” while 2 Sam 22:5 reads “waves.” The reading of the psalm has been influenced by the next verse (note “ropes of Sheol”) and perhaps also by Ps 116:3 (where “ropes of death” appears, as here, with the verb אָפַף, ’afaf). However, the parallelism of v. 4 (note “currents” in the next line) favors the reading “waves.” While the verb אָפַף is used with “ropes” as subject in Ps 116:3, it can also be used with engulfing “waters” as subject (see Jonah 2:5). Death is compared to surging waters in v. 4 and to a hunter in v. 5.
13 The Hebrew noun נַחַל (nakhal) usually refers to a river or stream, but in this context the plural form likely refers to the currents of the sea (see vv. 15–16).
14 The noun בְלִיַּעַל (véliyya’al) is used here as an epithet for death. Elsewhere it is a common noun meaning “wickedness, uselessness.” It is often associated with rebellion against authority and other crimes that result in societal disorder and anarchy. The phrase “man/son of wickedness” refers to one who opposes God and the order he has established. The term becomes an appropriate title for death, which, through human forces, launches an attack against God’s chosen servant.
15 In this poetic narrative context the prefixed verbal form is best understood as a preterite indicating past tense, not an imperfect. (Note the perfect verbal form in the parallel/preceding line.) The verb בָּעַת (ba’at) sometimes by metonymy carries the nuance “frighten,” but the parallelism (see “engulfed”) favors the meaning “overwhelm” here.