*Minor differences ignored. Grouped by changes, with first version listed as example.
But thou art the same - ואתה הוא veattah Hu, but thou art He, that is, The Eternal; and, consequently, he who only has immortality.
Thy years shall have no end - לא יתמו lo yittammu, "they shall not be completed." Every thing has its revolution - its conception, growth, perfection, decay, dissolution, and death, or corruption. It may be said that regeneration restores all these substances; and so it does in a measure, but not without deterioration. The breed of animals, as well as vegetables, wears out; but God's eternal round has no completion. I repeat it, - what is necessarily eternal is unchangeable and imperishable; all created beings are perishable and mutable, because not eternal. God alone is eternal; therefore God alone is imperishable and immutable.
But thou art the same,.... That hast created them, as the Targum adds; or "thou art he" (h), the everlasting I AM, the unchangeable Jehovah; immutable in his nature and perfections; in his love and affections to his people; in his power to protect and keep them; in his wisdom to guide and direct them; in his righteousness to clothe them, and render them acceptable to God; in his blood to cleanse them, and speak peace and pardon to them; in his fulness to supply them, and in his intercession for them,
and thy years shall have no end; See Gill on Psalm 102:24, now he, that made the heavens and the earth, and will be when they will not be, especially in the present form they are, must be able to rebuild his Zion, and bring on the glory he has promised; and from his eternity and immutability may be concluded the continuance of his church and interest in the world, until all the glorious things spoken of it shall be fulfilled, as follows.
(h) "tu ipse", Pagninus, Montanus.
*More commentary available at chapter level.