John 9:4

I must work the works of him that sent me
This shows, that the works of God, that were to be manifest, were to be done by Christ: many were the works which the Father gave him to do, and which he undertook to perform; and therefore there was a necessity of doing them, as principally the work of redemption, by fulfilling the law, and satisfying justice: and besides this, there were the preaching of the Gospel, and doing of miracles, and among these was this of giving sight to the blind, see ( Isaiah 35:5 ) , both in a natural and spiritual sense: and with a view to this he speaks of the works he mast do,

while it is day;
while the day of life lasts, for in the grave there is no work nor device:

the night cometh when no man can work;
meaning the night of death, and of the grave, and suggesting his own death hereby, that he had but a little time to be in this world, and therefore would make the best use of it, to do the will and work of his Father that sent him; and which should be a pattern to us. This life is but short, it is but as the length of a day; a great deal of business is to be done; and death is hastening on, which will put a period to all working.