Concerning thy testimonies, I have known of old,.... Or, "from thy testimonies, I have known of old" d: by carefully reading the Scriptures which testify of God, his mind an will, and frequently meditating on them, he had learned a long time ago, even from his youth, what follows,
that thou hast founded them for ever; that the things contained in them are sure and certain, established and eternal truths; the moral law and the precepts of it are eternal, and of perpetual obligation; not one jot or tittle of them shall ever fail; the Gospel, and the truths of it, are everlasting, and shall ever remain; in spite of all the opposition, craft and cunning, fury and force of men, to undermine and root them out; see Psalms 119:89.
d מעדתיך "ex obtestationibus tuis", Tigurine version; so Cocceius, Gejerus.