Juxtaposition (antithesis) is a common enough phenomenon in both Greek and Latin literature.
It may manifest itself in any number of ways, involving concepts (dark and light, as in Lucretius 5.978: tenebras … lucem), a politically loaded lexicon ([imperial] senate and princeps, as in Tacitus Ann. 6.10: apud senatum … apud principem), mere vocabulary (old and new, as in Cicero Phil. 2.25: vetera … recens), and so forth. It may (as in the citation below) or may not entail immediate physical abutment.
At 1.2.1 my interest was piqued:
Is [viz. Orgetorix], M. Messalla et M. Pupio Pisone consulibus, regni cupiditate inductus coniurationem nobilitatis fecit …
What appeals to me here is the not un-ironic (see following paragraph) juxtaposition of consulibus and regni, two terms of freighted significance in a late Republican context such as this one. In these opening sections of de bello gallico Caesar is setting up the arrogant Orgetorix – and his fellow conspirators in the bid for supreme power over all Gaul (1.3.7: … totius Galliae sese potiri posse sperant.), the Aeduan Dumnorix and the Sequanian Casticus — for a great fall. What better way to anticipate this collapse than to frame it in the emotionally weighted terminology of Republican (consulibus) politics in juxtaposition to that fetishized nightmare of the first-century nobility, kingly (reg-ni) supremacy and control? It is the reg- of regnum, the same stem as in rex (< reg-s), that is the incendiary messenger in this physical clash of words.
Why ‘not un-ironic’? What, and how deep, had Caesar’s personal involvement really been with that recent and famous Catilinarian coniuratio of 63 B.C.E. (cf. Sallust Cat. 49)? And not all that many years (i.e., in 44 B.C.E.) after the events here portrayed (i.e., in 58 B.C.E.), for what reason, in the eyes of many a Roman noble, would Caesar be killed, regni cupiditate inductus as he himself no doubt was?