I am a beacon, to warn men from setting up false beacons to mislead them. I am a buoy

I am a beacon, to warn men from setting up false beacons to mislead them. I am a buoy, to point out the channel, where they may safely erect beacons. I am a mark, to show the way, where they may safely erect beacons. I am a light, to guide them in erecting beacons, so that they may point out to other men the way, where they may safely erect beacons. I am a landmark, to show