I am an orthodox Muslim quantum engineer from Pakistan
When, at the discovery of biblical well of Hagar peace be upon her ( Zamzam) , ‘Abdul-Muttalib encountered the enmity of Quraish, he was quite worried because he had only one son to help him. He, therefore, prayed to Allah, making a nadhr (vow) that if Allah gave him ten sons to help him against his enemies, he would sacrifice one of them to please Allah. His prayer was granted, and Allah gave him twelve sons, out of whom five are famous in the Islamic history: ‘Abdullah, Abu Talib, Hamza, ‘Abbas and Abu Lahab. The other seven were: Harith (already mentioned), Zubayr, Ghaydaq, Muqawwim, Dharar, Qutham., and Hijl (or Mughira). He had six daughters: ‘Atikah, Umaymah, Baydha’, Barrah, Safiyyah, and Arwi.
When ten sons were born, ‘Abdul-Muttalib decided to sacrifice one of them according to his nadhr. Lot was cast and ‘Abdullah’s name came out. ‘Abdullah was the dearest to him, but he did not flinch from the decision of the fate. He took ‘Abdullah’s hands and started towards the place where sacrifices were offered. His daughters started crying and begged him to sacrifice ten camels in place of ‘Abdullah. At first ‘Abdul-Muttalib refused.
But when the pressure of the whole family (and in fact, the whole tribe) mounted, he agreed to cast lot between ‘Abdullah and ten camels. Again the name of ‘Abdullah came out. On the suggestion of the people, the number of the camels was increased to twenty, again, the same result. Repeatedly, the number was increased to thirty, forty, fifty, sixty, seventy, eighty and ninety. But the result was always the same. At last the lot was cast between 100 camels and ‘Abdullah.
Now the lot came out for the camels. The family was jubilant, but ‘Abdul Muttalib was not satisfied. He said: “Ten times the name of ‘Abdullah has come out. It is not fair to ignore those lots just for one lot." Three times more, he repeated the lot between Abdullah and 100 camels, and every time the lot came out for the camels. Then he sacrificed the camels and the life of ‘Abdullah was saved.
It was to this incident that the Holy Prophet referred when he said: “I am the son of the two sacrifices." He meant the sacrifices of Isma’iI and ‘Abdullah.