What the Bible says about Peace and Evil
(From Forerunner Commentary)
Until this point, the prophecy foretells a wonderful event, but verse 7 introduces a sobering side of God's work: He creates calamity! He links two contrasting sets of events: light and peace—representing constructive, hopeful, encouraging events—against darkness and calamity—representing destructive, fearful, discouraging circumstances. God creates both "good" and "bad" circumstances for His people and purpose.
John W. Ritenbaugh
God's Sovereignty and the Church's Condition (Part One)