《韩非子·外储说左上》
这怎么行呢？ 文公解下车子左边的马沉到河里，对着河神起了誓。
乃解左骖而盟于河。
"How can that be?". Duke Wen unhitched the horse from the left side of his chariot and released it into the river, after which he swore an oath by the river.