Let Your Light Shine Before Men.

Let your light so shine before men:
Here Christ applies the foregoing simile to his disciples, and more fully opens the meaning and design of it. His sense is this; that the light of the Gospel, which he had communicated to them, the spiritual knowledge of the mysteries of grace, which he had favoured them with, were to be openly declared, and made manifest before men. Light was not given merely for their own private use, but for the public good of mankind; and therefore, as they were placed as lights in the world, they were to hold forth, in the most open and conspicuous manner, the word of light and life:

that they may see your good works:
meaning their zeal and fervency; their plainness and openness; their sincerity, faithfulness, and integrity; their courage and intrepidity; their diligence, industry, and indefatigableness in preaching the Gospel; their strict regard to truth, the honour of Christ, and the good of souls; as also their very great care and concern to recommend the doctrines of grace, by their example in their lives and conversations:

and glorify your Father which is in heaven;
that is, that when the ministration of the Gospel has been blessed, for the illumination of the minds of men, to a thorough conviction of their state; and for their regeneration, conversion, sanctification, and comfort; they may give praise to God, and bless his name for qualifying and sending such Gospel ministers to show unto them the way of salvation; and that the word has been made useful to them for communicating spiritual light, life, joy, and comfort, (Mymvbv wnyba) , "Our and your Father which is in heaven", is a name, appellation, or periphrasis of God, frequently used by Jewish writers; and is often expressed by Christ in these his sermons on the mount. - John Gill