What is Benjamin saying in thesis VI in On the Concept of History?

I quote it in full from [here][1], having annotated the key points I'm struggling with in bold

> To articulate what is past does not mean to recognize “how it really
> was.” It means to take control of a memory, as it flashes in a moment
> of danger [**what does this mean?**]. For historical materialism it is a question of holding fast
> to a picture of the past [**to how it really was?**], just as if it had unexpectedly thrust
> itself, in a moment of danger, on the historical subject. The danger
> threatens the stock of tradition [**the dead?**] as much as its recipients. For both
> it is one and the same: handing itself over as the tool of the ruling
> classes. In every epoch, the attempt must be made to deliver tradition
> anew from the conformism which is on the point of overwhelming it [**is this an argument and if so how can it be paraphrased?**]. For
> the Messiah [**the rest of this thesis is beyond me**] arrives not merely as the Redeemer; he also arrives as the
> vanquisher of the Anti-christ. The only writer of history with the
> gift of setting alight the sparks of hope in the past, is the one who
> is convinced of this: that not even the dead will be safe from the
> enemy, if he is victorious. And this enemy has not ceased to be
> victorious.

To be specific, I'm confused as to why he appears to be defending a messianic version of historical materialism, when thesis 1 seems to say that 

> historical materialism [is actually][2] a quasi-religious fraud


  [1]: http://members.efn.org/~dredmond/ThesesonHistory.html
  [2]: https://en.wikipedia.org/wiki/Theses_on_the_Philosophy_of_History