despite > rage; malice rusty > blood-stained; dirty; rusty
5 And fretting grief, the enemy of life;
fretting > devouring; gnawing (cf. 106.44:5)
6 All these, and many evils more, haunt Ire,
Ire > [Wrath]
7 The swelling spleen, and frenzy raging rife,
spleen > {Spite; the organ itself, with which anger and spite were associated}
8 The shaking palsy, and Saint Francis' fire:
Saint Francis' fire > {Erysipelas, a skin disease characterized by a deep red colour}
9 Such one was Wrath, the last of this ungodly tire.