John Trapp on Psalms 68:24

Verſ. 24.Diod. They have ſeen thy goings, O God] Namely, the holy manner of conducting the Ark with even and proportionable reſtings, and ſettings down. See 2 Sam. 6.13. The Ark is here and elſewhere called, God, becauſe a ſymbol of his ſpecial preſence. When we are called to hear Gods Word, and pray publickly, though we ſee not God,ab. yet we may ſee his goings: Deus enim ipſe chorum agit, & primas tenet in illo inceſſu.

Of my God, my King] David though he were a King, yet held himſelf but Gods Mandatary, or Subſtitute.