Faith by its very nature must be tried, and the real trial of faith is not that we find it difficult to trust God, but that God's character has to be cleared in our own minds. Faith in its actual working out has to go through spells of unsyllabled isolation... 'Though He slay me, yet will I trust Him.' - this is the most sublime utterance of faith in the whole of the Bible.
The Golden Book of Oswald Chambers: My Utmost for His Highest; Selections for the Year (ed. 1935)