Rest is something I keep on thinking about these days. Some people may say I think about it too much. Anyway one thing I keep coming back to is what I read many years ago by Scott Hafemann:
The Sabbath signifies something fundamental about God's relationship to his people: it is a weekly bulletin that God, as Creator of the world, not only can but also will meet Israel's needs, because she is his chosen people. God called Israel to keep the Sabbath because, of all the peoples of the world, God created Israel to be his people. The Sabbath thus stood firm as a divinely established memorial to the covenant commitment God had made to his people. For her part, Israel was to "rest on the Sabbath" as a reminder of what she should do every day in relationship to the Creator who is committed to be her Provider: "call upon him" to meet her needs. God "keeps the Sabbath" by working for his people; his people "keep the Sabbath" by trusting him to do so.
(p. 49, The God of Promise and the Life of Faith)
Have you ever thought that all your service may actually be an expression of unbelief? Mine often is. Sadly often my rest is just laziness though. Can't get away from sin!
