A proverb meaning 'time is money' — time is valuable and should not be wasted, comparable to money in value.
祖父はいつも『時は金なり』と言って、時間を大切にしていた。
My grandfather always said 'time is money' and valued his time.
無駄な会議を減らすべきだ。時は金なりだから。
We should cut down on pointless meetings — time is money.