As a courtesy, please read the thread before interjecting straw man arguments. Had you done so, you would have seen my comment, "The God of Calvinism, like the God of Islam, is one who acts with pure will and is therefore completely unrestrained by any principle or reason" was a REPLY to this post, whereby a poster claimed God is not restrained by anything...
This concept and description of God (like the Islamic concept) demonstrates a belief that God is one who acts with pure will.
God is either Logos or Voluntas; that is, either reason or pure will. If He acts with pure will, then He acts above and contra-reason. He is unconstrained by any principle or any reason and capriciousness is essential to His very nature. Thus He can and does act completely arbitrarily (hence some are randomly elect while others were created simply for God to take pleasure in destroying). In Calvinism (and Islam), God acts Voluntas.
By contrast, if He is the Logos, then by His nature He acts with reason and love. Therefore to not act in accordance with reason and love would be contrary to His very nature. Thus in Christianity, God is in fact restrained by His own goodness. He cannot do that which is contrary to His nature.