If a wise man hold his body with its three erect parts (chest, neck, and head) even, and turn his senses with the mind towards the heart, he will then in the boat of Brahman cross all the torrents which cause fear.

In plain words: A wise person sits with chest, neck and head straight and steady. He turns his senses and mind inward toward the heart. Then Brahman is like a boat that carries him across all the floods of fear.