A.T. Robertson Commentary John 9:4

"We must work the works of him that sent me, while it is day: the night cometh, when no man can work." — John 9:4 (ASV)

We must work the works of him that sent me (ημας δε εργαζεσθα τα εργα του πεμψαντος με). This is undoubtedly the correct text (supported by the Neutral and Western classes) and not εμε (I) and με (me) of the Syrian class nor ημας (we) and ημας (us) of the Alexandrian class. Jesus associates us with him in the task committed to him by the Father. Bernard argues vigorously, but vainly, for εμε me. We are not able to fathom the depth of the necessity (δε) here involved in each life as in this poor blind man and in each of us.

While it is day (εως ημερα εστιν). This clause gives the note of urgency upon us all.

The night cometh (ερχετα νυξ). "Night is coming on," and rapidly. Night was coming for Jesus (7:33) and for each of us. Cf. 11:9; 12:35. Even electric lights do not turn night into day. Hεως with the present indicative (21:22f.) means "while," not until as in 13:38.