Stealing, in the sense of the Hebrew word ganav, refers to both the act of carrying off by stealth that which is not one's own (i.e., theft), but also to the deceptive inner disposition that accompanies the action. And ultimately that deceptive inner disposition is a form of self-deception.
None of us really "owns" anything at all, since God alone is the Creator and Giver of all of life. Stealing arrogantly (and vainly) attempts to seize some "thing" and to claim it for oneself - blindly disregarding the fact that "in Him we live and move and have our being" (Acts 17:28).
At bottom, stealing is an act based on fear, since the attitude behind the action evidences a lack of trust that God will meet all our needs.