Psalms 89:36 Midrash

אַ֭חַת נִשְׁבַּ֣עְתִּי בְקָדְשִׁ֑י אִֽם־לְדָוִ֥ד אֲכַזֵּֽב׃

Once have I sworn by My holiness: Surely I will not be false unto David;