Seneca, de Beneficiis 2.20:
There used to be a debate about Marcus Brutus, and whether he ought to have accepted the pardon of his life from Julius Caesar, when he thought that Caesar was to be slain. We will deal elsewhere with the reason which he followed for murdering him. To me, though he was a great man in other matters, Brutus seems to have made a huge mistake and not to have conducted himself in the Stoic manner. Either he feared the very name of king, since the best form of government is one under a just king, or he hoped that there would be liberty there where there was such a great reward of commanding and of serving, or he thought that the state could be recalled to its earlier form, though its ancient virtues had been loss, and thought further that there would then be an equality of civil law, that the laws would stand in their place, where he saw that so many thousands of men were fighting not about whether they would be slaves, but to whom.
How much he forgot either of the nature of things or of his own city! He believed not only that, following the death of one man, there would not be another who wished to do the same thing, though Tarquinius had been discovered after so many kings had been killed by sword and by lightning. But he ought to have accepted his life, but not to have held him in the place of a parent, because Caesar had come into the right of giving a benefice only through injustice. For Caesar did not save him by not killing him, nor did he give him a benefit, but only a reprieve.
Disputari de M. Bruto solet, an debuerit accipere ab divo Iulio vitam, cum occidendum eum iudicaret. Quam rationem in occidendo secutus sit, alias tractabimus; mihi enim, cum vir magnus in aliis fuerit, in hac re videtur vehementer errasse nec ex institutione Stoica se egisse; qui aut regis nomen extimuit, cum optimus civitatis status sub rege iusto sit, aut ibi speravit libertatem futuram, ubi tam magnum praemium erat et imperandi et serviendi, aut existimavit civitatem in priorem formam posse revocari amissis pristinis moribus futuramque ibi aequalitatem civilis iuris et staturas suo loco leges, ubi viderat tot milia hominum pugnantia, non an servirent, sed utri. Quanta vero illum aut rerum naturae aut urbis suae tenuit oblivio, qui uno interempto defuturum credidit alium, qui idem vellet, cum Tarquinius esset inventus post tot reges ferro ac fulminibus occisos! Sed vitam accipere debuit, ob hoc tamen <non> habere illum parentis loco, quia in ius dandi beneficii iniuria venerat; non enim servavit is, qui non interfecit, nec beneficium dedit, sed missionem.