4.I must work the works of him who hath sent me. He now testifies that he has been sent for the purpose of manifesting the kindness of God in giving sight to the blind man. He borrows also a comparison from the ordinary custom of life; for, when the sun is risen, man rises to labor, but the night is allotted to repose, as it is said,
The sun riseth; man goeth forth to his work, and to his labor, till the evening
He therefore employs the word Day to denote the time which the Father had fixed, during which he must finish the work assigned him; in the same manner as every man who has been called to some public office ought to be employed in what may be called his daily task, to perform what the nature of his office demands. Hence too we ought to deduce a universal rule, that to every man the course of his life may be called his day Wherefore, as the short duration of the light ought to excite laborers to industry and toil, that the darkness of the night may not come on them by surprise, ere their exertions are well begun, so, when we see that a short period of life is allotted to us, we ought to be ashamed of languishing in idleness. In short, as soon as God enlightens us by calling us, we ought to make no delay, that the opportunity may not be lost.