Muslims around the world are currently celebrating the Islamic holiday of Eid al-Ada, which commemorates Abraham’s willingness to sacrifice his son Ishmael when God had commanded him to do so, testing Abraham’s faith and resolve.
The Quran recounts the incident:
My Lord, grant me [a child] from among the righteous.” So We gave him good tidings of a forbearing boy. And when he reached with him [the age of] exertion, he said, “O my son, indeed I have seen in a dream that I [must] sacrifice you, so see what you think.” He said, “O my father, do as you are commanded. You will find me, if Allah wills, of the steadfast.” And when they had both submitted and he put him down upon his forehead, We called to him, “O Abraham, You have fulfilled the vision.” Indeed, We thus reward the doers of good. Indeed, this was the clear trial. And We ransomed him with a great sacrifice, And We left for him [favorable mention] among later generations: “Peace upon Abraham.” (37:100-109)
Abraham had longed for a child, and God had finally heard Abraham’s prayers and granted him a son, once Ishmael had grown up he had a dream and vision that he was to sacrifice his son Ishmael, and he brought this to the attention of Ishmael, who told his father that he must go through with it if this is what God had intended.
This was obviously a very hard decision for Abraham, he had patiently waited for a son, and finally he had been granted a son, and then he was told to sacrifice his son, his only son at the time Ishmael.
Even with the hardship though, Abraham agreed to do the task, showing his very strong and determined faith, which is the entire moral of the story, to show how faithful Abraham was, and this is the example that all believers seek to emulate and follow.
Once the moment came for Abraham to sacrifice his son, he hears a voice calling to him telling him that this was only a test for Abraham, that God had never really intended for Abraham to sacrifice his son Ishmael, he was just testing Abraham to see how he would react and what he would do. In Ishmael’s place a ram was put instead and Abraham sacrifice the ram, and this is why Muslims during Eid al-Adha also sacrifice the ram.
So Muslims during Eid al-Adha are remembering this momentous sacrifice, and the momentous faith Abraham had displayed when he was tested by God.