'Thirty' in the Bible

All the presidents of the kingdom, the governors, and the princes, the counsellers, and the captains, have consulted together to establish a royal statute, and to make a firm decree, that whosoever shall ask a petition of any God or man for thirty days, save of thee, O king, he shall be cast into the den of lions.

Then they came near, and spake before the king concerning the king's decree; Hast thou not signed a decree, that every man that shall ask a petition of any God or man within thirty days, save of thee, O king, shall be cast into the den of lions? The king answered and said, The thing is true, according to the law of the Medes and Persians, which altereth not.

Blessed is he that waiteth, and cometh to the thousand three hundred and five and thirty days.