Help on yzing a macbeth quote ?

Lady Macbeth is exclaiming her excitement that Macbeth is now in higher positions (and she knows it is possible he may become king if this is after she learned of the "prophecy") However she is scared that Macbeth may become too powerful even for her (which essentially happens when he doesn't care about her when she dies in the end. Also, in the beginning they both pionately love each other, however with the addition of power to Macbeth's status, their love dwindles as the power pulls them apart). I don't quite remember the theme...I think it may have been something along the lines of "Be careful what you wish for." but there are many themes to this anyways!