時の経つのは早いものだ

The phrase combines several common Japanese elements. '時 (toki)' means 'time'. '経つ (tatsu)' means 'to pass' or 'to elapse'. 'の (no)' is a particle indicating possession or acting as a nominalizer. 'は (wa)' is a topic particle, marking '時の経つ (the passing of time)' as the subject. '早い (hayai)' means 'fast' or 'early'. 'もの (mono)' here is a nominalizer that can also express a sense of wonder, observation, or mild exclamation. 'だ (da)' is a copula, making it a declarative statement. Historically, the concept of time passing quickly is a universal human experience and has been expressed in various forms in Japanese literature and daily speech for centuries. The direct phrasing '時の経つのは早いものだ' is a very natural and common way to express this sentiment in modern Japanese. While there isn't a single definitive historical 'origin' story for this exact phrase, its components have been in use for a very long time, reflecting the ongoing human contemplation of time's swiftness. It's an idiomatic expression that has evolved organically through common usage rather than being coined at a specific point by a known individual.