כִּֽי־אָמַ֗רְתִּי ע֭וֹלָם חֶ֣סֶד יִבָּנֶ֑ה שָׁמַ֓יִם ׀ תָּכִ֖ן אֱמוּנָתְךָ֣ בָהֶֽם׃
For I have said: 'For ever is mercy built; In the very heavens Thou dost establish Thy faithfulness.
Read kabbalistic (mystical) interpretation of Psalms 89:3: and classical mystical sources.