But not only by communion, but also by conduct, must we keep in the light. The fugitive found outside the city of refuge was fair game for the avenger, and if he strayed beyond its bounds there was a sword in his back before he knew where he was. Every Christian, by each sin, whether it be acted or only thought, casts himself out of the light into the darkness that rings it round, and out there he is a victim to the beasts of prey that hunt in darkness. An eclipse of the sun is not caused by any change in the sun, but by an opaque body, the offspring and satellite of the earth, coming between the earth and sun. And so, when Christian men lose the light of God's face, it is not because there is any 'variableness or shadow of turning' in Him, but because between Him and them has come the blackness--their own offspring--of their own sin. You are not safe if you are outside the light of His countenance. These are the conditions of security. III. Lastly, note what the hidden ones find in the light. This burst of confidence in my text comes from the Psalmist immediately after plaintively pouring out his soul under the pressure of afflictions. His experience may teach us the interpretation of his glad assurance. God will keep all real evil from us if we keep near Him; but He will not keep the externals that men call evil from us. I do not know whether there is such a thing as filtering any poisons or malaria by means of light, but I am sure that the light of God filters our atmosphere for us. Though it may leave the external form of evil it takes all the poison out of it and turns it into a harmless minister for our good. The arrows that are launched at us may be tipped with venom when they leave the bow, but if they pass through the radiant envelope of divine protection that surrounds us--and they must have passed through that if they reach us--it cleanses all the venom from the points though it leaves the sharpness there. The evil is not an evil if it has got our length; and its having touched us shows that He who lets it pass into the light where His children safely dwell, knows that it cannot harm them.