Then the scum appears!

(Thomas Brooks, "The Mute Christian Under the Smarting Rod" or, "The Silent Soul with Sovereign Antidotes" 1659)

"I have tried you in the furnace of affliction." Isaiah 48:10

Few Christians see themselves and understand themselves rightfully.
By trials, God reveals much of a man's sinful self to his pious self.

When the fire is put under the pot—then the scum appears!
Just so, when God tries a poor soul, Oh! how does . . .
  the scum of pride,
  the scum of murmuring,
  the scum of distrust,
  the scum of impatience,
  the scum of worldliness,
  the scum of carnality,
  the scum of foolishness,
  the scum of willfulness
—reveal itself in the heart of the poor creature!

Trials are God's looking-glass, in which His people see their own faults. Oh! . . .
  that looseness,
  that vileness,
  that wretchedness,
  that sink of filthiness,
  that gulf of wickedness,
which trials show to be in their hearts!

"When He has tried me, I shall come forth as gold!" Job 23:10

"Trials make the promise sweet,
 Trials give new life to prayer;
 Trials bring me to His feet,
 Lay me low, and keep me there!"

   ~ ~ ~ ~

For those who desire additional devotional reading, here is a comforting two page article by Arthur Pink, "Sufferings Compensated".