Ephrem the Syrian : Certainly it had been decided by Darius to save Daniel from the present danger with any possible means; therefore he sealed the entrance of the den with his own signet and invited the satraps to do the same. This had to be done for two reasons: first, in order that [the satraps] might not steal there without being seen and, after rolling off the lid, might kill him; second, in order that they might not spread among the people the rumor that some fraud had been used inside the den. — COMMENTARY ON Daniel 6:17 Hippolytus of Rome : "And they brought a stone and set at the mouth of the den and the king sealed it with his signet ring," [Daniel 6:17] that the matter may not be changed regarding Daniel. And this was a malicious deed, for the satraps were cautious, lest secretly the king command Daniel to be drawn out of the den and so they thought fit to seal the stone. In which manner also the chiefs of the Pharisees did to the Savior having sealed the stone with a guard. [Matthew 27:66] — Commentary on Daniel 3.27.3-5 Jerome : Verse 17. "A single stone was brought and placed over the opening of the pit, and the king sealed it with his ring..." He sealed with his ring the rock by which the opening of the pit was shut up, so that the enemies of Daniel might not make any attempt to harm him. For he had entrusted him to the power of God, and although not worried about lions, he was fearful of men. He also sealed it with the ring of his nobles, in order to avoid all ground for suspicion so far as they were concerned. — St. Jerome, Commentary on Daniel, CHAPTER SIX