Thy way is in the sea; rather, was in the sea. Thou wentest, i.e; in person before thy people in their passage across the dry bed of the Red Sea; truly there, though invisible (comp. Exodus 15:13; Psalms 78:52, Psalms 78:53; Psalms 106:9; Isaiah 63:13).
And thy path in the great waters; literally, thy paths. So the Revised Version. And thy footsteps are not known; rather, were not. No one perceived thy presence, much less discerned thy footsteps. As in external nature and in the human heart, God worked secretly.