The phrase "sacrifice of one's son" refers to the act of giving up or losing something that is dear to you, often in the context of a parent giving up their child for some greater purpose or goal. Full definition
Certainly he told the people that the sacrifices of animals he offered were worthless in itself, and only valuable, if they would be considered as a reminder for the future sacrifice of the Son of God, the only sacrifice which can take away sins. (religion.blogs.cnn.com)
Why did a loving God need the blood sacrifice of His son for God to be able to forgive humankind of its sins? (nakedpastor.com)
(ENTIRE BOOK) The great mid-nineteenth century Danish poet - philosopher, in this classic philosophical text, explores, through the story of Abraham and his willing sacrifice of his son Issac, the nature of belief. (religion-online.org)