וְהַ֨דָּבָ֔ר אֲשֶׁ֥ר דִּבַּ֖רְנוּ אֲנִ֣י וָאָ֑תָּה הִנֵּ֧ה יְהוָ֛ה בֵּינִ֥י וּבֵינְךָ֖ עַד־עוֹלָֽם׃ (ס)
And as touching the matter which I and thou have spoken of, behold, the LORD is between me and thee for ever.’
Read kabbalistic (mystical) interpretation of I Samuel 20:23: and classical mystical sources.