לָ֭רֹכֵב בִּשְׁמֵ֣י שְׁמֵי־קֶ֑דֶם הֵ֥ן יִתֵּ֥ן בְּ֝קוֹלוֹ ק֣וֹל עֹֽז׃
To Him that rideth upon the heavens of heavens, which are of old; Lo, He uttereth His voice, a mighty voice.
Read kabbalistic (mystical) interpretation of Psalms 68:34: and classical mystical sources.