In matā tabʿathūhā tabʿathūhā dhamīmatan, repetition is meaningful rather than ornamental. The first verb states the condition—you stir war; the second points to the outcome, that you bring it forth in an odious form. Matā serves as a conditional adverb of time.
Idhā ḍarraytumūhā introduces another time-conditioned process, leading to fa-taḍram. The cumulative structure warns that people can set a conflict in motion without being able to contain its subsequent consequences.