כִּ֤י זֶ֨ה ׀ אֱלֹהִ֣ים אֱ֭לֹהֵינוּ עוֹלָ֣ם וָעֶ֑ד ה֖וּא יְנַהֲגֵ֣נוּ עַל־מֽוּת׃
For such is God, our God, for ever and ever; He will guide us eternally.
Rashi on Psalms
as in youth Heb. על-מות, as a man who leads his young son slowly. Menachem (p. 133) interpreted it as an expression of eternity, and so is its interpretation: will lead us to eternity.