There is none like to God, O Jeshurun,
Who rides on the heavens for your help,
And in his excellency on the skies.
Israel is now assured that that what Moses has spoken of will be theirs, for there is no god like their God. He is king in Jeshurun (Deuteronomy 33:5), and now He is their God. He is supreme and alone in majesty. He rules them from above and can come to their help from there at any time. For this compare Psalms 68:33-34 where a similar idea is expressed. See also Psalms 104:3; Isa 19:1; 2 Samuel 22:10-11; Psalms 18:9-10. He rides the Heavens in order to come to their aid, and is supreme in the skies.
Baal, a prominent god both in Canaan and in Baal worship in Egypt, was described as ‘the rider of the clouds', and Moses wants it to be quite clear that the clouds are in fact part of Yahweh's sphere. It is rather He Who rides the clouds.