'Trouble' in the Bible

“Then Daniel, whose [Babylonian] name was Belteshazzar, was appalled and speechless for a while [because he was deeply concerned about the destiny of the king], and his thoughts alarmed him. The king said, ‘Belteshazzar, do not let the dream or its interpretation frighten you.’ Belteshazzar answered, ‘My lord, may the dream be [meant] for those who hate you and its message for your enemies!

“Now at that [end] time Michael, the great [angelic] prince who stands guard over the children of your people, will arise. And there will be a time of distress such as never occurred since there was a nation until that time; but at that time your people, everyone who is found written in the Book [of Life], will be rescued.