(The Christian's) whole out look upon everything that happens to (him) should be governed by three things: my realization of who i am, my consciousness of where i am going, and me knowledge of what awaits me when i get there. You will find this argument in many places in Scripture. The apostle Paul once put it like this, 'our light affliction, which is but for a moment, worketh for us a far more exceeding and eternal weight of glory;while we look not at the things that are seen but at the things that are not seen. For the things which are seen are temporal; but the things which are not seen are eternal.' (2 Corinthians 4:17-18) The Christian should always be looking at that.
Martin Lloyd-Jones, Studies in the Sermon on the Mount, Vol 1, P 144