16 It is to the love of this light that I would exhort you, Beloved; that you would cry out by your works, when the Lord “passes by;” let the voice of faith sound out, that “Jesus standing still,” that is, the Unchangeable, Abiding Wisdom of God, and the Majesty of the Word of God, “by which all things were made,” may open your eyes. The same Tobias in giving advice to his son, instructed him to this, to cry out; that is, he instructed him to good works. He told him to give to the poor, charged him to give alms to the needy, and taught him, saying, “My son, alms suffers not to come into darkness.” The blind gave counsel for receiving and gaining light.
“Alms,” says he, “suffers not to come into darkness.” Had his son in astonishment answered him, What then, father, have you not given alms, that you now speakest to me in blindness; are you not in darkness, and yet you say to me, “Alms suffers not to come into darkness.” But no, he knew well what the light was, concerning which he gave his son instruction, he knew well what he saw in the inner man. The son held out his hand to his father, to enable him to walk on earth; and the father to the son, to enable him to dwell in heaven.
Source: Sermons on Selected Lessons of the New Testament (New Advent)