3 And eke the hag, with many a bitter threat,

eke > also

4 Still called upon to kill him in the place.

Still > Continuously upon > [upon Furor] in the place > there; on the spot, right away

5 With whose reproach and odious menace 6 The knight, emboiling in his haughty heart,

emboiling > boiling with rage (SUS)

7 Knit all his forces, and gan soon unbrace

gan soon unbrace > did immediately loosen

8 His grasping hold: so lightly did upstart,

lightly > quickly, lightly upstart > get up