1-thessalonians 5:5

Ye are all the children of light - Ye are children of God, and enjoy both his light and life. Ye are Christians - ye belong to him who has brought life and immortality to light by his Gospel. This dispensation, under which ye are, has illustrated all the preceding dispensations; in its light all is become luminous; and ye, who walked formerly in heathen ignorance, or in the darkness of Jewish prejudices, are now light in the Lord, because ye have believed in him who is the light to lighten the Gentiles, and the glory and splendor of his people Israel.

We are not of the night, nor of darkness - Our actions are such as we are not afraid to expose to the fullest and clearest light. Sinners hate the light; they are enemies to knowledge; they love darkness; they will not receive instructions; and their deeds are such as cannot bear the light.

Ye are all the children of light - All who are Christians. The phrase" children of light" is a Hebraism, meaning that they were the enlightened children of God.

And the children of the day - Who live as if light always shone round about them. The meaning is, that in reference to the coming of the Lord they are as people would be in reference to the coming of a thief, if there were no night and no necessity of slumber. They would always be wakeful and active, and it would be impossible to come upon them by surprise. Christians are always to be wakeful and vigilant; they are so to expect the coming of the Redeemer, that he will not find them off their guard, and will not come upon them by surprise.