Every Cloud Has A Silver Lining

Idiom: Every cloud has a silver lining
OED definition: Every difficult or sad situation has a comforting or more hopeful aspect, even though this may not be immediately apparent
Example: After a difficult week, he tried to remember that every cloud has a silver lining.

This idiom comes from the fact that if you look closely at dark and stormy clouds, you can often see the sun trying to shine through them. This results in a dark cloud with what looks like a brighter, silvery edge. Based on this, many people use this idiom to suggest that even though a situation may seem dark and difficult, the sun will always shine through in the end, resulting in a positive outcome.
The phrase ‘Silver lining’ was coined by John Milton in 1634 and can be seen in his work Comus. Since then, ‘silver linings’ have frequently been used in literature and due to the origin of the phrase, these ‘silver linings’ have often been referred to as Milton’s clouds. In the Victorian period, a similar phrase to the one we use today was favoured. The Dublin Magazine published a review of the novel Marian by Mrs S Hall in 1840 and included the following:
“There’s a silver lining to every cloud that sails about the heavens if we could only see it.”

The current wording of the expression was first seen in P.T. Barnum’s book Struggles and Triumphs in 1869:

“‘Every cloud,’ says the proverb, ‘has a silver lining,’ and so I did not despair.'”
The phrase has remained unchanged since then, however, has not lost its popularity as it continues to be used to provide comfort to people when they are experiencing difficult times.