Walking in light prevents stumbling; walking in darkness leaves a person without direction.

⁹Jesus answered, Are there not twelve hours in the day? If any man walk in the day, he stumbleth not, because he seeth the light of this world.

¹⁰But if a man walk in the night, he stumbleth, because there is no light in him.

³⁵Then Jesus said unto them, Yet a little while is the light with you. Walk while ye have the light, lest darkness come upon you: for he that walketh in darkness knoweth not whither he goeth.