According to the biblical account in Daniel 6, Daniel was cast into the den of lions because he continued to pray to God despite a royal decree forbidding it.

It is important to note, however, that Daniel did not hide his actions. Jealous officials tricked King Darius into signing an irrevocable law that, for 30 days, anyone who prayed to any god or man other than the king would be thrown to the lions.

When Daniel learned of the law, he went home to his upstairs room and prayed with his windows open toward Jerusalem, just as he had always done. Rather than hiding (which would have been cowardice) or making a public spectacle (which would have been pride), he simply maintained his usual spiritual discipline in a visible way. His enemies, who were watching him, caught him in the act of praying and reported him to the king to force the execution of the law.