"But Minerva, your own child—" I began and then I saw it did hurt her to make this sacrifice she was convinced she needed to make. (2.8.60)
Patria asks her sister to take her son, Manolito, because she is going to be traveling a lot for her revolutionary activities. Patria, ever the mother, at first doesn't understand how anyone could give up their child; but she realizes that it isn't that her sister doesn't care. It's that she's making an enormous sacrifice for what she believes in.
She looked at me a long moment, and very simply, she said, "I know you want to stay out of trouble, and I respect that."
"If there should come a time—" I said.
"There will," she said. (2.8.65-67)
Minerva is making a sacrifice by giving up her son to her sister; Patria isn't ready to do so, but expresses her support for her sister's movement. The ominous words "There will" is foreshadowing. It lets the reader know that things are intense and that they are only going to require even more sacrifice from the characters
If you were caught harboring any enemies of the regime even if you yourself were not involved in their schemes, you would be jailed, and everything you owned would become the property of the government.
His land! Worked by his father and grandfather and great-grandfather before him. (2.8.145-146)
Pedrito doesn't want to allow the revolutionaries to meet on his property because of the new law that would take away his land, which is his life, if he were caught. But he makes the sacrifice, which puts his entire family history and heritage on the line, because of his love for his wife and son and his beliefs.
Even so, that night, her ears still ringing from Jaimito's shout, Dedé had been ready to risk her life. It was her marriage that she couldn't put on the line. (3.9.66)
All of the sisters must make sacrifices in order to join the movement. Minerva and Mate lose their freedom and Patria loses her son. But Dedé is the only one who doesn't have the support of her husband. It's easy to condemn her for cowardice, but she is the only one who is faced with sacrificing her marriage.
It wasn't just that she couldn't bear losing her boys, although that in itself was a dread large enough to stop her in her tracks. She also couldn't desert them. Who would stand between them and the raised hand when their father lost his temper? Who would make them mangú the way they liked it, cut their hair so it looked right, and sit in the dark with them when they were scared and the next morning not remind them she had been there? (3.9.121)
Dedé is being asked to sacrifice her marriage in order to join her sisters, but by doing so she would lose contact with her boys. She frames her decision not to join as a sacrifice: she must sacrifice her involvement in order to be there for her sons when they need her.
And Nelson and Pedrito, seeing the conflagration and fearing for Patria and the children, came running down from the hills, their hands over their heads, giving themselves up. (3.9.225)
Nelson and Pedrito could have escaped the horrors of prison if they had kept running, but they sacrifice their freedom because of their fear for Patria, Noris, and Raúl Enrique. They are willing to literally "give themselves up" because of the family ties they feel for the others.
"Take me instead, please." Patria knelt by the door, pleading with Captain Peña. "I beg you for the love of God." (3.9.249)
Patria begs Captain Peña to bargain with her, offering up herself as a sacrifice in place of her sister Mate. Her words, "for the love of God" call to mind the Christian idea of sacrifice in Jesus Christ's death, which was meant to take the place of all sinners' deaths.
I don't know how it happened that my cross became bearable. We have a saying around here, the humpback never gets tired carrying his burden on his back. All at once, I lost my home, my husband, my son, my peace of mind. But after a couple of weeks living at Mamá's, I got used to the sorrows heaped upon my heart. (3.10.1)
That Christian imagery we mentioned in the previous quote is even clearer here. Patria talks about "her cross," which is a metaphor for her burdens, the loss of her home and family. Just as Jesus had to carry the cross he would be executed on, Patria must carry the sorrows of her life with bravery.
Hear my cry, Jefe. Release my sisters and their husbands and mine. But most especially, I beg you, oh Jefe, give me back my son. Take me instead, I'll be your sacrificial lamb. (3.10.30-31)
When her prayers don't work, Patria begins dealing with Trujillo himself, praying to his portrait and calling him by his nickname, Jefe (Chief). She knows that she can't just beg, and must offer him something in exchange. Her ultimate sacrifice is to offer herself in exchange for her family's lives.
"Your husband was offered his freedom and his farm back—"
My heart leapt!
"—if he proved his loyalty to El Jefe by divorcing his Mirabal wife."
"Oh?" I could feel my heart like a hand making a fist in my chest.
[…] "You Mirabal women must be something else" […]. (3.10.47-51)
See what we mean? El Jefe doesn't give anything away for free. He requires sacrifice from all of his subjects. His offer to Pedrito is crazy, obviously; Pedrito is willing to sacrifice his freedom and possibly his life in order to maintain his marriage to Patria.