Keith Mathison's post "Homesick Pilgrims" touches on the biblical theme of believers as "aliens and strangers on earth" (Heb. 11:13). This is a theme that will be addressed in depth by the Rev. Jason J. Stellman in his book Pilgrim Theology: Worship and Life between the Already and the Not Yet, coming in June from Reformation Trust Publishing. To whet your appetite, here are a couple of excerpts:

From the preface:

The central thesis of this book is that the new covenant situates us in a tension between "the already" on the one hand and the "not yet" on the other. For God's people under the old covenant before the coming of Christ, most of God's promises fell into the category of "not yet," or as yet unfulfilled. The expectation of Israel was that the long-awaited Messiah would come and immediately fulfill all of the remaining Old Testament prophecies, thereby replacing the "not yet" of future expectation with the "already" of present enjoyment of the divine promises. What God's people did not expect, however, was a Messiah who would inaugurate a kingdom in His first advent while waiting to fully consummate it until His second coming, leaving His people to live in the gap between the partial and complete fulfillment of His promises. God's delay in ushering in the kingdom in its glorious and final form means that we live in the intersection of the present and the future as exiles and pilgrims in the divinely ordained overlap of the ages. And as should be expected, this biblical motif shapes our identity at every turn. Therefore, both worship and life, our activities in the sacred and secular realms, should reflect the sense of homesickness and longing that all sojourners feel.

From the introduction:

Let the reader always remember, however, that being a pilgrim means more than just being homeless. There is a final destination, an eternal city, a true theocracy that awaits all who have been baptized into Christ Jesus. In this heavenly abode, there will be no serpents to distrust or Canaanites to dispel, for "No longer will there be anything accursed, but the throne of God and of the Lamb will be in it, and his servants will worship him. They will see his face, and his name will be on their foreheads. And night will be no more. They will need no light of lamp or sun, for the Lord God will be their light, and they will reign forever and ever"(Rev. 22:3-5).

Do you long for this "building of God, a house not made with hands" (2 Cor. 5:1), compared to which the sufferings of this present time appear as mere trifles unworthy of mention? I hope that you do, for this is what it means to be a pilgrim.