But when I read my text I learn that they are not mere passive reflectors. They are to give light not merely as polished mirrors hung in the sunbeams; they are to shine from within, as well as on the surface. There must be a settled aim and purpose to scatter light about them. "Let your light so shine," says Christ. The word "_so_" here implies that you have a deep responsibility as to the kind of light you give, and the effect produced by it. It is a light which must be made to shine through your good works, your holy lives. And those works must be prosecuted in such a way that men shall be led by them to "glorify your Father which is in heaven." Here is the great law of Christian activity: that all you do shall be done in a way which shall tell for the glory of God. Christian friend, here is the governing principle of your life. It requires you to act with reference to the good of others. It bids you keep ever in view the influence of your conduct upon those around you. 'Tis a high, a noble principle--the glory of God. 'Tis an unselfish principle, which will enable you to display to the world all the graces of a holy life without pride or ostentation, and so to walk that men will give God the glory of any good they find in you. Ah, we fear it is a principle too often wanting, even with those who profess to be God's people. Many have no objection to let their light shine while they can be appreciated; many are willing that others shall see their good works, and glorify themselves for them; many will devote their time and labor to the cause of Christ so long as they can have the preëminence, and impress others with the idea of their own importance. Their light will shine, but shine only to let the world see their own perfections, and pay homage to their sanctity. But far different from this is the spirit of a Christian's service. It is not self, but God who must have all the glory. Let it _so_ shine, says Christ, that it shall lead all who see it to render God the glory. Let ungodly men learn from your holy lives the reality and excellency of that salvation which you have tasted. Let the light of your example shine so that they too shall be led to seek the same divine illumination. Let all your works point them to that Redeemer who has called you out of darkness, and prompt them to seek him as their own. Thus will they glorify your Father which is in heaven. Such is the spirit of the Saviour's words before us, and the practical inquiry for us all is, How do our lives correspond with this spirit? First of all, have we really any light to shed around us? A mere profession is worthless as an empty lamp. Have our hearts been illuminated by divine grace? Has the darkness of guilt and ignorance and error been scattered there; and have we tasted the sweets of pardon, peace, and sanctification?