This is according to Leader of the Islamic Revolution Ayatollah Seyed Ali Khamenei, in a speech delivered on the occasion of Eid al-Adha in 2010:
“If we pay attention to the philosophy inherent in Eid al-Adha, many paths will be opened up for us. A select Messenger of the Righteous One, Prophet Abraham (pbuh), made a sacrifice on Eid al-Adha. In some cases, sacrificing your loved ones is beyond sacrificing your life. Prophet Abraham (pbuh) was about to sacrifice a loved one in the way of God-a young child whom Allah the Exalted had bestowed on him at an old age after a lifetime of waiting. "Praise be to Allah, Who has given me in old age Ismail and Ishaq. Most surely my Lord is the Hearer of prayer." (Holy Qur'an, 14: 39) Allah the Exalted had bestowed these two sons on him at an old age, probably after a lifetime of impatient waiting. He had no hope of getting another child at that age. The Chief of the Martyrs of the entire world, Imam Hussain (pbuh), who is the symbol of sacrifice and martyrdom, remembers this event in the holy prayer of Arafah: "And Abraham decided to sacrifice his son at an old age after waiting a lifetime." This is part of a supplication by Imam Hussain (pbuh) in Arafah, a supplication that was recited by Hajj pilgrims on Arafah Day.
This sacrifice is a symbol for the faithful people who want to tread the path of truth, transcendence and perfection. This is impossible without a sacrifice. In fact, all the tests that we go through involve one essential element-all tests involve a sacrifice. Sometimes this involves sacrificing your life and wealth. Other times it involves forgiving somebody for a comment he makes and insists on stubbornly. Yet other times it involves sacrificing your dear ones-your children and your loved ones. Being tested means going through hardships. When a hardship is placed in the way of an individual or a people, going through this hardship is a test. If they go through this hardship, they will reach the desired destination. And if they fail-if they fail to utilize the talent within them, if they fail to overcome their passions-they will fall by the wayside. This is what a test is. God does not put us through divine tests in order to get to know us and see at what level we are. Divine tests are in fact a step towards one's destination. When we are tested and we manage to go through the hardships of tests, we enter a new situation, a new stage of life. A nation and an individual are not different from one another in this regard.”
Imam Khamenei, Nov. 17, 2010