1 Chronicles 18

So the Lord preserved David wherever he went. v.6

Read chapter 18
This chapter speaks of David's victories in battle from the north, east, south and west.  Fulfilling what was foretold of some of these nations.  This wasn't David trying to fulfill a prophesy but letting it happen according to God's way.  The Lord preserved David.  The word preserve means to keep up or maintain.  God was keeping David alive to fulfill prophesy and promise.  This wasn't a preservation to keep alive forever but for the time God allotted to David.  Paul says in his letter to Timothy, "And the Lord will deliver me from every evil work and preserve me for His heavenly kingdom."  The same was of Paul as was to David, both used by God and preserved for His kingdom.  They will both be raised up into God's glorious kingdom one day.  Although they both are today dead they are not gone forever but are preserved by and for God.  
I love the last verse of Psalm 121 that comes to mind as I read this verse in 1 Chronicles: "The Lord shall preserve your going out and your coming in
From this time forth, and even forevermore."
Let us not fear death if we are in Christ for He preserves us.  And even while we are alive and have comings and goings in our life the Lord is preserving and watching over every move.  Take heart dear friend.