Compare lamb to the slaughter and Romeo and Juliet

The phrase "lamb to the slaughter" refers to an innocent being sacrificed for another's sin.
As we can easily see, Romeo and Juliet are two innocent lovers whose only crime is falling in love with one another. This love is a crime only because of the long-lasting feud between their two families. Romeo and Juliet did not start the feud, and they don't even appear to know why it exists. Yet because of it, their love is forbidden. They have to hide it and marry secretly lest their families get upset. In the end, because of all the secrecy and miscommunication around their marriage, the two commit suicide.
The shock of the two innocent and beloved young people killing themselves reconciles the families, who have realized too late the endlessly destructive power of the feud. The sacrifice of the young lovers wakes everyone up and heals the rift, but at the expense of the lives of two innocents themselves.