4 With horrible assault, and fury fell,
fell > fierce, terrible
5 They heaped huge strokes, the scorned life to quell,
the > (Each other's; and each is also careless of his own) quell > destroy; extinguish
6 That all on uproar from its settled seat
That > [So that]
7 The house was raised, and all that in did dwell; 8 Seemed that loud thunder with amazement great
Seemed > [It seemed] amazement > consternation, frenzy
9 Did rend the rattling skies with flames of fouldering heat.
fouldering > {Flashing or thundering forth; cf. 111.40:2}