They stand fast forever and ever - Margin, "established." The Hebrew word means "sustained, supported." They will not fail or fall. Whatever else may be shaken, his law, his word, and the principles of his administration, will not fail. See the notes at Matthew 5:18. Compare Luke 16:17; Matthew 24:35. The great principles of truth and righteousness will stand, and whatever is founded on those principles will endure forever.
And are done in truth and uprightness - Are based on truth, or on a just view of things; they are done in such a way that truth will be maintained and promoted. The word "uprightness" here means that all this is done on the principles of equity - of what "ought" to be done, or what is "best" to be done. Compare Psalm 19:9.

They stand fast for ever - סמוכים semuchim, they are propped up, buttressed, for ever. They can never fail; for God's power supports his works, and his providence preserves the record of what he has done.

They stand fast for ever and ever,.... Not only the covenant and its promises do, but both law and Gospel, the commandments of the one and the doctrines of the other; the law is an eternal law, as to the matter of it, and is not made void by faith, but established; and the Gospel is an everlasting Gospel, which lives and abides for ever, being established upon the word of God, which cannot be broken; and is continued in the church, the pillar and ground of truth, from whence it can never be removed.
And are done in truth and uprightness; either made by the Lord according to the truth of things, the moral perfections of his nature and will, and the rectitude of it; or observed by men that truly fear the Lord with great truth and sincerity.

Done - Constituted or ordered.