". . . For the LORD God, even my God is with you" (1 Chronicles 28:20).
See that? "EVEN MY GOD." David is encouraging his son, Solomon as he hands over the kingdom with all it's great responsibilities. But Solomon, I'm sure, is not surprised by David's "ownership" of the LORD God, for Jehovah had been David's mainstay throughout his life.
Paul does the same thing when he owns the gospel, "my gospel," and "But my God shall supply all your needs in glory in Christ Jesus" (Phil. 4:19?). So, David and Paul call God "MY God," or the gospel, "MY gospel."
How is it that we call God mine? I am quite certain that many who attend churches around this country (and the world) do so with little consideration that the One with whom they have to do is, in this sense--theirs. They show up to a building they did not buy, nor which they intend to "own" emotionally. They hear prayers prayed, songs sung, and sermons preached. They may even enter into these songs or messages and get something out of them. But they never--it seems--can say that they "own" them as their own. Such tend to keep a comfortable arm's distance away from faith all the while convinced that they are saved.
The dictionary even helps us here. Besides meaning "to possess," it defines "own" in terms of "doing something unaided," "taking responsibility for something," or to "acknowledge." When a friend or acquaintance of ours finally achieves a heightened degree of success in his or her art or vocation, we might say of them--"They've finally come into their own." An online "phrase finder" defines it thus: "To come into one's own" means literally to take possession of what is rightfully one's own property, and figuratively to begin to flourish and be happy and successful in a role that suits one. This fits quite well, actually, especially for the Christian who most literally has received an inheritance that is "imperishable, undefiled, and unfading, reserved in heaven" (1 Peter 1:4). But if the Christian (and this is the point isn't it) does not "own" this inheritance, then they cannot be said to have flourished, been happy in a role that Jesus suited to them! They merely, as it were, show up to class long enough to say "present" when the teacher calls the role. But that's it.
On the other hand, let me encourage all Christians to "own" the faith, to acknowledge God personally, deeply, intimately. Like Paul who cried out, "I want to know Christ and the power of His resurrection" (Phil. 3:10). It was his desire, and his desire drove his actions, defined his motives. To "own" Christ, then, fellow Christian, is at least to deeply desire Jesus.
Let me encourage us further to do this decidedly, determinedly, persistently, and perseveringly. This will change everything! These four adverbs call forth from us our will and determination even unto the end! Such a loving, gracious God demands that does He not? "For the LORD God, even MY God is with you."