Wait for the LORD; be strong, and let your heart take courage; wait for the LORD!
God knows the end and outcome of trial, which you do not know. "Hold on! I want to mix in the sugar in such a way that, even though you die, you are overwhelmed with perpetual joy in the resurrection of the dead." For these exercises are useful to this end, that we learn to understand the mercy of God and the mystery of faith and hope and in some manner comprehend the inscrutable plans of God concerning us, as is stated in Psalm 4:3: "Know that the Lord has set apart the godly for Himself," and likewise in Psalm 16:3: "As for the saints, they are the noble, in whom is all My delight," and in Psalm 17:7: "Wondrously show Thy steadfast love, O Savior of those who seek refuge from their adversaries at Thy right hand." Mercy, grace, and the promise are certainly present, but it is wonderfully fulfilled beyond all our thoughts, desires, and wishes.
From Lectures on Genesis (Luther's Works 6:354)