נֵצַח is a goal at a distance, and then the endurance that reaches toward it. Brown, Driver, and Briggs give brilliance or enduringness, and the adverbial use to everlasting or continually. Strong’s opens with a bright object traveled toward, then splendor, confidence, or continually—to the most distant point of view. The passage decides whether English wants forever, continually, always, never (with a negative), perpetual, end, or, rarely, eminence or strength.

It is not עוֹלָם, and it is not עַד. Those three lemmas are different roots. English “forever” and “always” are used for all of them, so the English word alone does not tell which Hebrew stands behind it. In the WOTA Bible, “forever,” “always,” and the other surfaces for this noun link here only where the Hebrew is נֵצַח.

Job 4:20 is לָנֶצַח beside “between morning and evening.” In the WOTA Bible that line is printed “They perish always,” not forever. Psalm 16:11 has נֶצַח without the preposition: pleasures always, not forever more. Isaiah 25:8 is לָנֶצַח: swallowed up death always. Under negation the same line becomes never: Amos 8:7, Isaiah 13:20.

Eminence and the vitality outlier

Almost every use is duration. BDB puts only two verses under eminence. In the WOTA Bible 1 Chronicles 29:11 prints “the eminence” in the attribute list beside greatness, power, glory, and majesty. 1 Samuel 15:29, נֵצַח יִשְׂרָאֵל, keeps “the Strength of Israel” as that eminence title.

Lamentations 3:18 is the useful outlier. The Hebrew is נִצְחִי, “my netsach.” BDB files it under enduring of life. In the WOTA Bible it is printed “My strength has perished.” Here strength is the right English when it means vitality—the speaker’s lasting life-force and endurance collapsing—not muscle, and not the time-adverb “always.” The line shows why “strength” belongs in the range for this noun without turning the usual לָנֶצַח verses into that sense.

Verses sometimes set this noun beside עוֹלָם. Psalm 103:9 has לָנֶצַח as “always” and לְעוֹלָם as “forever.” Isaiah 57:16 reverses the English: לְעוֹלָם is “forever,” לָנֶצַח is “always.” Isaiah 34:10 has smoke forever (עוֹלָם), then לְנֵצַח נְצָחִים as “forever and ever.”