Harmony makes small things grow, lack of it makes great things decay.

Gaius Sallustius Crispus (Sallust), a Roman historian and former politician writing in the late Roman Republic (1st century BCE), repeatedly framed Rome’s crises as moral and civic failures—especially the erosion of concord (concordia) and the rise of faction (factio). The sentiment behind this quotation aligns with Sallust’s habit of contrasting earlier Roman unity and discipline with later internal rivalry and corruption, themes that run through his historical monographs on the Catilinarian conspiracy and the Jugurthine War. In that milieu, “harmony” is not private tranquility but political and social cohesion: the shared commitment that allows a community to flourish, and whose absence causes even powerful states to rot from within.

The aphorism argues that collective success depends less on sheer size or resources than on concord. When people cooperate—within a household, an army, or a state—limited means can be amplified into lasting achievement (“small things grow”). Conversely, greatness is fragile if undermined by internal division: rivalry, distrust, and factionalism waste energy and corrode institutions, so that even “great things” decline. The line reflects a classical republican moral: civic virtue is relational, sustained by shared purpose and mutual restraint. It also offers a diagnostic of political decay—external threats matter, but internal disunity is often the decisive cause of collapse.