A man had a herd of 250 cows and took great care looking after their welfare.
One day, however, a tiger ate one of them—and when the man noticed this, he thought, “I’ve lost one of my cows, and my herd is incomplete. What’s the point of having all these other cows?” And with that, the man drove all the cows off a cliff and to their death.
He is like a person who, after breaking just one precept of righteousness, thinks, “I’ve broken one, so I might as well abandon them all.”