mihi, etc., i.e. I have been not only spared myself but am allowed to appear for another.
studus, zealous efforts. The thought is that Caesar is accustomed to decide such cases not with reference to any pleading or any wish to gratify his own friends but rather with reference to the character of the petitioners and their relation to the defendant.
causas, the cause.
voltus, the tears and lamentations by which it was customary to seek acquittal (see peroration of Defence of Milo).
quam taus necessarius, how closely connected with you.
fruuntur, concedas: the indic. refers to individual cases; the subj. characterizes Caesar himself, but the difference is slight.
justissimum, best founded.