II Chronicles 6:17 Kabbalah

וְעַתָּ֕ה יְהוָ֖ה אֱלֹהֵ֣י יִשְׂרָאֵ֑ל יֵֽאָמֵן֙ דְּבָ֣רְךָ֔ אֲשֶׁ֥ר דִּבַּ֖רְתָּ לְעַבְדְּךָ֥ לְדָוִֽיד׃

Now therefore, O LORD, the God of Israel, let Thy word be verified, which Thou spokest unto Thy servant David.

Read kabbalistic (mystical) interpretation of II Chronicles 6:17: and classical mystical sources.