Neither can an infinite series of producing causes be allowed because in causes there must necessarily be some order as to prior and posterior. But an infinite series of producing causes rejects all order, for then no cause would be first; rather all would be middle, having some preceding cause. Indeed there would be no cause which ought not to have infinite superior causes before itself which is impossible [asystaton]). If there were infinite causes before each and every cause, before the whole multitude and collection of causes there would be infinite causes and thus that collection would not be total.
Francis Turretin, Institutes of Elenctic Theology, Third Topic, Question I, Section VI (Giger, tr.).