Jamieson, Fausset and Brown on Ezekiel 12:4

4. by day--in broad daylight, when all can see thee.

at even--not contradicting the words "by day." The baggage was to be sent before by day, and Ezekiel was to follow at nightfall [Grotius]; or, the preparations were to be made by day, the actual departure was to be effected at night [Henderson].

as they that go forth into captivity--literally, "as the goings forth of the captivity," that is, of the captive band of exiles, namely, amid the silent darkness: typifying Zedekiah's flight by night on the taking of the city (Jr 39:4; 52:7).