The same faith, which on the previous evening had led Darius to seal the entrance of the den, brought him again to that place, as if he would have seen Daniel still alive.
Verse 19. "Then the king arose at the break of dawn and proceeded with haste to the pit of lions." The term "pit" (lacus) implies a really deep depression, or dry cistern, in which the lions were fed. And so he proceeded hastily to the pit at the break of dawn, believing that Daniel was alive. But in Latin the word lacus is applied to a body of fresh water, such as Lake Benacus and Lake Larius, and the rest of them. The Greeks call it limne, that is, "a body of standing water" (stagnum).
“King Darius rose early at daybreak,” that is, while it was still dark, around dawn, so that there was even need of lamps (the meaning of “at daybreak”).
[AD 373] Ephrem the Syrian on Daniel 6:19