What does Daniel 6:15 mean?

Jealous rivals tricked Darius, king over Babylon, into passing an unchangeable law secretly meant to target Daniel (Daniel 6:1–9). The king was distraught when he realized what had happened, but his culture did not allow such decrees to be changed. Nor could they be overruled or defied (Daniel 6:10–13; Esther 8:8). Now, the conspirators have returned to press the king to make good on his own law. He cannot delay any longer. Rather than disrupt established law, he will sentence Daniel to be locked into an enclosure with lions (Daniel 6:16).

By referring again to the irrevocable law of the Medes and the Persians, Daniel's accusers are appealing to Darius's reputation. How would it look to his subjects if he blatantly countered the principles of his own kingdom? Even worse to do so for a disobedient Jewish exile (Daniel 1:1–7). This reaction, including Darius's delay (Daniel 6:14), shows a major contrast to the personality of Nebuchadnezzar. Nebuchadnezzar reacted quickly and violently to disobedience (Daniel 3:19–22). Darius was reluctant to punish Daniel where his predecessor needed no prodding to carry out the death sentence. Daniel appears more like Pilate, the governor who reluctantly condemned Jesus rather than stand up to a mob (John 19:6, 12 16).