inretisses. Subjunctive, because the antecedent to 'quem' does not refer to any particular individual, but stands for a class.
ad audaciam, etc. The sword and the torch are the instruments by which 'audacia' and 'libido' attain their objects; the former to strike the blow, the latter to show the way in the darkness.
alio incredibili scelere. Sallust (Cat. 15) says that Catilina, wishing to marry the profligate Orestilla, poisoned his son because she objected to his presence. The further charge, that he had killed his first wife, is mentioned by Cicero alone.
aut non vindicata esse, understand 'si exstiterit.'
proximis Idibus. The Kalends, Nones, and Ides were the 'settling-days' at Rome. Cicero means that Catilina will realize his failure on the next settling-day, when his creditors will demand their money. Cf. Hor. Sat. 1. 3. 87 'Cum misero tristes venere Kalendae,' and Epodes 2. 69 'Omnem redegit Idibus pecuniam, Curat Kalendis ponere,' where the money-lender calls in his money on the Ides of one month, and on the Kalends of the next lends it out again.
te pridie Kalendas, etc., i.e. December 31, 66 b.c. This refers to the so-called 'first conspiracy,' on which see [Introduction, page 8].
comitio. The singular comitium denotes the place of assembly; the plural comitia the assembly itself.
mentem, 'reflection.'