Adam Clarke's Bible Commentary Verse 2. Mercy shall be built up for ever ] God's goodness is the foundation on which his mercy rests; and from that source, and on that foundation, acts of mercy shall flow and be built up for ever and ever.
Thy faithfulness shalt thou establish ] What thou hast promised to do to the children of men on earth, thou dost register in heaven, and thy promise shall never fail.
Matthew Henry Commentary
Verses 1-4 - Though our expectations may be disappointed, yet God's promises ar established in the heavens, in his eternal counsels; they are out of the reach of opposers in hell and earth. And faith in the boundles mercy and everlasting truth of God, may bring comfort even in the deepest trials.
Original Hebrew כי3588 אמרתי559 עולם5769 חסד2617 יבנה1129 שׁמים8064 תכן3559 אמונתך׃530