If you never found time to read Eagleton’s Holy Terror then this article in Lapham’s Quarterly is a pretty good summary of all his main arguments.
The Grand Inquisitor ranks among those who regard God as their adversary. He believes that like a brutal despot, God loads on men and women more than they can bear; the burden he loads on them is known not as tithe or tax but freedom. However, this overlooks God’s own solidarity with human weakness, which is known as Jesus. On Calvary, God proves feeble and fleshly even unto death. His only signifier is the tortured body of one who spoke out for love and justice and was done to death by the state. Only if one can look on this terrible failure and still live can one lay a foundation for anything more edifying. Only by being entombed in the earth can one reach for the sky. It is in the place of excrement, as Yeats reminds us, that love has pitched his mansion. Any moral idealism that refuses this truth is just so much ideology.
In relation to this, you might want to check out a pretty much unread review that Eagleton wrote in 2008 of Rowan Williams’s book on Dostoevsky.