Charles H. Spurgeon on Psalms 89:1

For ever. I know some join in oeternum to the noun misercordias, and not to the verb cantabo, making the sense to be this: I will always sing thy mercies which endure for ever. But always is referred as well, if not better, unto the verb, I will sing: as who would say, Lord, thy mercies are so manifest, and so manifold, so great in their number, and so good in their nature, that I will alway, so long as I have any being, sing praises unto thee Haply some will object, "All flesh is grass, and the goodliness thereof is as the flower of the field: the grass withereth, the flower fadeth", (Isa 40:6-7). David being persecuted by Saul, said, "There is but a step between me and death", (1Sa 20:3). Nay, David, thy life is shorter than a stride, but "a span long", as thyself witnesseth, Ps 39:5. How can he then that begs his bread but for a day promise to spend his breath in magnifying the Lord for ever? Answer is made, that the prophet will not only commend the mercies of the Lord in word, but also commit them unto writing. Ut sciat hoec oetas, posteritasque legat (Eobanus Hessus.) (that this age may know, and that posterity may read.) As the tongue of the prophet is termed elsewhere "the pen of a writer"; so the writing of the Prophet is here termed his mouth, as Euthymeus upon the place (Ac 4:25), Liber Psalmorum os David (The Book of Psalms is the mouth of David). He doth intend to note the mercies of God, and to set forth his truth in a book, the which he will leave behind him (as an instrument) to convey the same from generation to generations, from the generation of Jews to the generation of Christians. Or from the Old Testament to the New: for the blessed Apostles in their sermons usually cite sentences out of the Psalms. S. Peter telleth us that the gospel was preached unto the dead (1Pe 4:6); so may we say, that the gospel is preached by the dead. For the most ancient fathers, and other judicious authors, who have spent their days in writing learned expositions and godly meditations upon the Holy Scriptures, although they be dead, yet they "sing all the mercies of the Lord, and shew the truth of his word from one generation to another." It is reported in our chronicles of Athelstan, parum oetati vixit, multum glorioe (he lived but little of time, but much of glory). So many zealous and industrious doctors have lived (in respect of their age) but a little, yet in respect of their acts, a great while, shining still in their works and writings, as lights of the world. Or the prophet may be said to sing ever intentionally, though not actually. For as the wicked, if he could live alway, would sin alway, so the good man (if God should suffer him alway to breathe on earth) would sing alway the mercies of the Lord. —John Boys.