[Frodo2968thewhite]

Although your theory is interesting, it is indeed false. First of all, even though Sauron hated the Dwarves, he knew that he couldn't dominate using men alone, so he NEEDED the Dwarves on his side, not kill them. So he gave them the rings to prolong their life and "condemn" them to become evil, yet powerful, servents of Sauron. Secondly, Sauron did not know that a Balrog was in Moria UNTIL the Dwarves stumled upon it in TA 1980. It was then in 2480 that Sauron sent orcs and trolls to Moria, due to the recent discovery of the Ancient Demon of the Balrog of Khazad-Dum (commonly known as Durin's Bane). Thirdly, It is clearly stated that Sauron's plan with the Dwarven Rings FAILED, and so he tried to take them back because of their uselesness.