Therefore King Darius signed the written decree.
Daniel's adversaries could have no advantage against him from any law now in being; they therefore contrive a new law, by which they hope to ensnare him, and in a matter in which they knew they should be sure of him; and such was his fidelity to his God that they gained their point. Here is, I. Darius's impious law.
Commenting on Daniel 6:6-10
Wherefore King Darius signed the writing and the decree. Moved to it by the number and importunity of his principal men; and chiefly through affectation of deity, which this law gave him; and that he might have an opportunity of ingratiating himself into his new subjects by his munificence and liberality, not being aware of the snare laid for his favourite, Daniel.
Such a despotic decree is quite explicable by remembering that the king, as the incarnation of Ormuzd, might demand such an act of religious obedience as a test of loyalty. Persecuting laws are always made on false pretenses. Instead of bitter complaints against men, Daniel prays to God. Though having vast business as a ruler of the empire, he finds time to pray thrice a day.