Reddit reviews The Tale of the Heike

This is inaccurate. None of the major shrines ever existed to protect anyone from anything, they were all troublemakers.

Sōhei as a phenomenon were a great source of conflict and strife. If you read sources like the Heike Monogatari, you will find that as early as the 1180s (and right through into the sengoku jidai) entire monasteries effectively fielded armies and regularly fought one another over trifles. Sticking with the Heike Monogatari, it tells us that the Enryaku-ji and Mii-dera temples were heavily involved in the Gempei War, with not a few "monks" being thugs who just wanted to fight and merely shaved their hair to do so.

If you read the Helen Craig McCulloch translation, in chapter one you will find the section [15] "Petitioning with Sacred Palanquins [Mikoshi], which neatly illustrates how the Sōhei terrorised cities like Kyoto by generally trashing them then leaving behind portable shrines as a kind of a spiritual threat (to interpolate, the threat is the anger of spirits or gods contained within if the townsfolk fight back). It also partially reflects that the samurai as an institution only got going because of the Sōhei doing things like this, insamuch as house Taira and house Minamoto are only converged on the capital to guard the gate from these monks, who probably have as much to do with spirituality as I do to goat-juggling. You need to read between the lines, though, because epics like the Heike were usually an oral tradition passed down by monks.

Source: http://www.amazon.com/The-Tale-Heike-Helen-McCullough/dp/0804718032/ref=sr_1_1?ie=UTF8&qid=1341343180&sr=8-1&keywords=heike+monogatari

Really damn good as secondary reading: http://www.amazon.com/Samurai-Sacred-Stephen-Turnbull/dp/B005IUTGXO/ref=sr_1_1?s=books&ie=UTF8&qid=1341343212&sr=1-1&keywords=samurai+and+the+sacred