What is the meaning of the title of "Lamb to the Slaughter"?

From the Holy
Bible, Isaiah 53:7 says 

All of us like sheep have gone
astray, Each of us has turned to his own way; But the LORD has caused the  href="https://biblehub.com/isaiah/53-7.htm">iniquity of us all To fall on
Him. He was oppressed and He was afflicted, Yet He did not open His mouth; Like a lamb that is
led to slaughter, And like a sheep that is silent before its shearers, So He did not open His
mouth. 

The lamb represents any living being that is
innocently being led to a bad situation; one which could even end his or her life. 

In 's short story "," theis a woman whose life gravitates around her husband,
a policeman. She admires him, pampers him, is a good housewife and, to top it all, she is
heavily pregnant with their first child. 

The description of this woman
suggests that she is vulnerable and innocent. She is dependent on her man. She does not work,
for all we know, and her existence is based on the wants and needs of her husband. Still, one
night after work, he tells her that he is leaving her, making her an innocent person entering a
bad situation.

This piece of news is the trigger that leads Mary, the
protagonist, to suddenly lose her mind. Without planning or scheming, she simply goes to the
kitchen to cook her husband a leg of lamb. She takes it from the freezer and, almost
automatically, she turns around and pounds her husband's head with it, killing him instantly.
Was it blinding rage? We will never know. However, we do now this: this pregnant woman, whose
life depended on the man she just killed, will face prison and perhaps even the death penalty if
she is proven guilty. Then, she would be the lamb going to the slaughter. 

As
such, Mary has to protect herself and conceal the weapon that killed Patrick. How does she do
it? By feeding it to the policemen who come to the scene. She cooks the leg of lamb, feeds it to
them, makes her weapon disappear. and, like the story shows, 

...in the other room, Mary Maloney began to giggle. 

We can argue that there are two innocent people who go "to the slaughter."
The first is Patrick, Mary's husband. He is a mean man for leaving his pregnant wife, but he has
no idea that the outcome of this decision will be his death. The second person is Mary. If she
had been accused of her husband's death, she would have had to give birth in prison, give up her
child, and possibly face death. Theof the title is that the murder weapon is a leg of lamb,
which the policemen investigating the scene end up eating.