Respected brother Firasat,
First, please note that Hagar (Hajira) was the daughter of the king of Syria. She was no concubine as erroneously reported in the Bible.
Now the MOMENTOUS Sacrifice.
Al-Hamdulillah, QXP makes things crystal clear here as well.
37:100 (Abraham migrated to Syria and soon ruled a mighty empire, and prayed), “My Lord! Grant me a healthy child.”
37:101 So We gave him the good news of a clement son (Ishmael).
37:102 And when he was old enough to strive along with him, Abraham said, “O My dear son! I have a vision that I must give you to a life of test and tribulation for a Noble cause (37:107). So look, what do you think?” He said, “O My father! Do what you are commanded. God willing, you will find me of the steadfast.”
[Zibh and Zabh = Sacrifice = Disregard comfort for a Noble cause. Just as Qatl = To subdue, kill, fight, humiliate, bring low]
37:103 As both of them had surrendered themselves (to God), he made Ishmael prostrate on his forehead in gratitude. [Contrary to popular tradition, Abraham never envisioned or intended to slaughter his son. God does not play games with His servants]
37:104 We called unto him, “O Abraham!
37:105 You have already affirmed the vision. We – This is so - We must reward the doers of good.”
37:106 This was a trial, clear in itself. [Leaving the prestigious office of Chief Priesthood in Babylon and now the comfort of Syria for the wilderness of Makkah]
37:107 We exchanged his life for a Momentous Sacrifice. [Please notice here the absence of the Biblical and the traditional myth of a 'ram' sent from the heavens. Also, note that slaughtering of a sheep or goat, by no means, can be considered a Momentous Sacrifice. 14:37, 37:102]
37:108 And We left for him remembrance among the later generations.
37:109 Peace and salutation to Abraham!
37:110 Thus do We reward the benefactors of humanity.
37:111 He was one of Our truly believing servants.
37:112 We gave him the good news of Isaac, a Prophet, among those who fulfilled their potentials.