Concerning thy testimonies - In regard to all that thou hast testified to as true and best. Every command of God is in fact a testimony of his as to what is right; every promise is a testimony of his own purpose in regard to mankind.
I have known of old - The word used here is a noun, and means properly, “the front,” what is “before;” then, the East; then, what pertains to olden time or ancient days - “before” the present. The meaning here is, that he had known this “before” what had now occurred; it was not a new thing - a new experience. It was deeply impressed on his mind as the result of all his reflection and observation.
That thou hast founded them for ever - “From” eternity, and “for” eternity. They were laid in the eternity past; they will continue in the eternity to come. They are based on eternal principles of right; they will never be changed. Such a conviction will do much to keep the soul steady and firm in the trials and uncertainties of life. Whatever may change, God’s law does not change; whatever is new, that is not new; whatever will vanish away, that will remain.