Once have I sworn by my holiness that I will not lie unto David. Once have I sworn - I have made one determination on this head, and have bound myself by my holiness; it is impossible that I should change, and there needs no second oath, the one already made is of endless obligation.
Related Commentaries of Psalms 89:35
Psalms 89:35
35 Once have I sworn by my holiness that I will not lie unto David.