You are the light of the world. A city that is set on a hill cannot be hid.
All Commentaries on Matthew 5:14 Go To Matthew 5
Hilary of Poitiers
AD 368
It is the nature of a light to emit its rays whithersoever it is carried about, and when brought into a house to dispel the darkness of that house. Thus the world, placed beyond the pale of the knowledge of God, was held in the darkness of ignorance, till the light of knowledge was brought to it by the Apostles, and thenceforward the knowledge of God shone bright, and from their small bodies, whithersoever they went about, light is ministered to the darkness.
Or, the city signifies the flesh which He had taken on Him; because that in Himby this assumption of human nature, there was as it were a collection of the human race, and we by partaking in His flesh become inhabitants of that city. He cannot therefore be hid, because being set in the height of God’s power, Heis offered to be contemplated of all men in admiration of his works.
Or, the Lord likened the Synagogue to a corn-measure, which only receiving within itself such fruit as was raised; contained a certain measure of limited obedience.
Or, the lamp, i.e. Christ Himself, is set on its stand when He was suspended on the Cross in His passion, to give light for ever to those that dwell in the Church; “to give light,” He says, “to all that are in the house. "Or, “the house” may be the world itself, according to what He said above, “Ye are the light of the world.”.
He instructs the Apostles to shine with such a light, that in the admiration of their work God may be praised, “Let your light so shine before men, that they may see your good works.”.
He means not that we should seek glory of men, but that though we conceal it, our work may shine forth in honour of God to those among whom we live.