Isma'il A (Ishmael) was the elder son of Ibrahim A (Abraham). Both of them were Rasul (Messenger) of Allah (God). The final Messenger of Allah, Muhammad S was a direct descendent of Isma'il A (Ishmael).

Rusul (Messengers) of Islam, Christianity and Judaism were all from the family of his father Ibrahim A (Abraham).

When his father Ibrahim A (Abraham) began spreading the message of Allah (God) among his people, they did not agree with him and wanted him to leave their town. 

Ibrahim A (Abraham) migrated (Made Hijrah) from his native place Ur with his wife Sarah and his nephew Lut A (Lot), also a Rasul (Messenger) of Allah (God).

Ibrahim A (Abraham) stayed in Filastin (Palestine) for some time before moving to Misr (Egypt) to spread the Message of Allah (God). Lut A (Lot) stayed back in Filastin (Palestine).

In the beginning, the King of Misr (Egypt) tried to misbehave with his family, but when he found out that Ibrahim A (Abraham) was a Rasul (Messenger) of Allah (God), he repented and sent his daughter Hajar (Hagar) to serve him.

Ibrahim A (Abraham) and his wife Sarah did not have any child after many years of their marriage. Sarah asked Ibrahim A (Abraham) to marry Hajar (Hagar), to get an heir. Soon after their marriage, Hajar (Hagar) gave birth to a son Isma'il A (Ishmael).

Sarah still did not have any child of her own. She began to feel uncomfortable in living with Hajar (Hagar) and her son Isma'il A (Ishmael).

One day Sarah told Ibrahim A (Abraham) that she did not want to live with Hajar (Hagar) and her son Isma'il A (Ishmael), any more.
Allah (God) commanded Ibrahim A (Abraham) to take Hajar (Hagar) and Isma'il A (Ishmael) to a far away place.
After a long journey, they arrived at the valley of Makkah in Arabia. That was a very hostile place and the valley was completely barren. The valley of Makkah was on the route of caravans that traveled between Sham (Syria) and Yaman (Yemen), but did not stop there because there was no water or vegetation in that area. No one lived there because the area was inhabitable.

Ibrahim A (Abraham) told Hajar (Hagar) that he is leaving them in the valley of Makkah to fulfill the wish of Allah (God). He prayed for the safety of Hajar (Hagar) and Isma'il A (Ishmael) before returning.

He prayed to Allah (God) to look after his family before he embarked on his return journey.

“O our Lord! I have made some of my offspring to dwell in an uncultivable valley
by Your Sacred House (the Ka’bah at Makkah) in order, O our Lord, that they
may perform As-Salah (Iqamat-as-Salah). So fill some hears among men with
love towards them, and (O Allah) provide them with fruits so that they may give
thanks.
Surah (Chapter) Ibrahim (Abraham) The Qur-an 14:37

Ibrahim A (Abraham) returned to Sarah after leaving some food and water for Hajar (Hagar) and Isma'il A (Ishmael).

The supply of water exhausted some time after Ibrahim A (Abraham) went back. When infant Isma'il A (Ishmael) got very thirsty, his mother Hajar (Hagar) went in search of water. She put Isma'il A (Ishmael) on ground and ran atop a hillock to locate water. When she could not see any source of water from there, she ran down and climbed another nearby hillock. She ran between these two hills several times but could not locate any source of water within the visible distance. In desperation, Hajar (Hagar) prayed to Allah (God) for help. Allah (God) sent Jibril A (Gabriel), a Malak (Angel) to help them, and made the spring of Zamzam to appear there.

Hajar (Hagar) and Isma'il A (Ishmael) settled near the Zamzam well, in the valley of Makkah and served caravans which passed through that area. The valley of Makkah became a popular stop for the caravans because of water. With time, nomadic tribes, which usually roamed in search of water, settled down near Zamzam. Jurham tribe was one of the first tribes that settled there. This was the beginning of the city of Makkah.
Hajar (Hagar) and Isma'il A (Ishmael) were the first inhabitants of the city of Makkah. 

Muslims commemorate the Sa’i (Attempt) of Hajar (Hagar) in finding water for her son Isma’il A (Ishmael) as one of the key rituals of Hajj (Pilgrimage to the Ka’bah) and ‘Umrah (Lesser Pilgrimage to the Ka’bah); by running between the hills of Safa and Marwah seven times.

Back in Misr (Egypt), Sarah gave birth to Ishaq A (Isaac) when she was quite old.

Although Ibrahim A (Abraham) had another son Ishaq A (Isaac); he was always worried about Hajar (Hagar) and Isma'il A (Ishmael) and always prayed to Allah (God) for their safety and well being. Finally, he decided to visit his family; he had left in the valley of Makkah many years ago. He thanked Allah (God) when he found Hajar (Hagar) and Isma'il A (Ishmael) living there happily.
After his first trip to his family in a long time, Ibrahim A (Abraham) continued to visit them in Makkah.

During several such trips to Makkah, Ibrahim A (Abraham) constructed the Ka'bah with the help of his elder son Isma'il A (Ishmael).


And (remember) when Ibrahim (Abraham) and (his son) Isma’il (Ishmael) were  raising the foundations of the House (the Ka’bah at Makkah), (saying), “Our } Lord! Accept (this service) from us. Verily! You are the All-Hearer,  the All-Knower.”
Surah (Chapter) Al-Baqarah (The Cow) The Qur-an 2:127

Allah (God) told Ibrahim A (Abraham) about the site for the construction of the Ka'bah.


And (remember) when We showed Ibrahim (Abraham) the site of the (Sacred) House (the Ka’bah at Makkah) (saying): “Associate not anything (in worship) with Me, [La ilaha illallah (none has the right to be worshipped but Allah) –  Islamic Monotheism], and sanctify My House for those who circumambulate it,  and those who stand up (for prayer), and those who bow (submit themselves  with humility and obedience to Allah), and make prostration (in prayer);”
Surah (Chapter) Al Hajj (The Pilgrimage) The Qur-an 22:26

Ibrahim A (Abraham) and Isma’il A (Ishmael) prayed to Allah (God) after constructing the Ka'bah for the people of Makkah.    

“Our Lord! Send amongst them a Messenger of their own (and indeed Allah answered their invocations by sending Muhammad S), who shall recite unto them Your Verses and instruct them in the Book (this Qur’an) and Al-Hikmah (full knowledge of the Islamic laws and jurisprudence or wisdom or Prophethood),
and purify them. Verily! You are the All-Mighty, the All-Wise.”
Surah (Chapter) Al-Baqarah (The Cow) The Qur-an 2:129

After his visits to Makkah, Ibrahim A (Abraham) used to return to his first wife Sarah and his younger son Ishaq A (Isaac). He came to settle down at Makkah with Hajar (Hagar) and Isma'il A (Ishmael), after Sarah died. His younger son Ishaq A (Isaac) had grown up by then.

Once, while living in Makkah, Ibrahim A (Abraham) saw a dream that Allah (God) wanted him to sacrifice his son Isma'il A (Ishmael), who being his elder son was very dear to him. Being an obedient servant of Allah (God), he without any hesitation, decided to sacrifice Isma'il A (Ishmael).

Ibrahim A (Abraham) told Isma'il A (Ishmael) about his decision, who readily agreed for it. He was also glad to know that he was chosen by his Lord, Allah (God) for the sacrifice. Ibrahim A (Abraham) took Isma'il A (Ishmael) near the hill of Marwah, the ancient site for sacrificing animals, for performing the sacrifice.

Ibrahim A (Abraham) and Isma'il A (Ishmael) both got ready for the sacrifice. Allah (God) saved Isma'il A (Ishmael) in time and replaced him with a ram. Allah (God) rewarded both of them for their steadfastness and total submission and faithfulness to Him.

 
And, when he (his son) was old enough to walk with him, he said: “O my son!
I have seen a dream that I am slaughtering you (offering you in sacrifice
to Allah).
So look what you think! He said: “O my father! Do that which you are commanded, Insha” Allah (if Allah wills), you shall find me of As-Sabirun (the patient).”


Then, when they had both submitted themselves (to
the Will of Allah), and he had laid him prostrate on his
forehead (or on the side of his forehead for slaughtering);


We called out to him: “O Ibrahim (Abraham)!

You have fulfilled the dream!” Verily thus do we reward the Muhsinin
(ggod-doers).

 
Verily, that indeed was a manifest trial.

And We ransomed him with a great sacrifice (i.e. a ram);

And We left for him (a goodly remembrance)
among the later generations.

“Salam (peace) be upon Ibrahim
(Abraham)!”
Surah (Chapter) As-Saffat (Those Ranged in Ranks) The Qur-an 37:102-109

Muslims remember this great sacrifice all over the world and sacrifice animals to commemorate the event during ‘Id-al-Adh-ha  (The Festival of Sacrifice) each year.

This sacrifice is done in the month of Dhul Hijjah (Twelfth month of the Islamic Calendar).

Ibrahim A (Abraham) was especially blessed by Allah (God), for coming out successfully from severe tests that He subjected him to.

And (remember) when the Lord of Ibrahim (Abraham) [i.e. Allah] tried him with  (certain) commands, which he fulfilled. He (Allah) said (to him), “Verily, I am  going to make you an Imam (a leader) for mankind (to follow you).” [Ibrahim (Abraham)] said, “And of my offspring (to make leaders).” (Allah) said, “My  Covenant (Prophethood) includes not Zalimun (Polytheists and wrong-doers).”
Surah (Chapter) Al-Baqarah (The Cow) The Qur-an 2:124

Allah (God) amply rewarded Ibrahim A (Abraham) and Isma'il A (Ishmael) for their obedience.

Isma'il A (Ishmael) married Ra'lah, daughter of Mudad bin 'Amr, the chief of Jurham tribe. They had twelve children - each becoming an ancestor of the twelve Arabian tribes. Their eldest son Nabat became the caretaker of the Ka'bah after Isma'il A (Ishmael).
Mudad bin 'Amr became the caretaker of the Ka'bah after his son-in-law Nabat died. The custodianship of the Ka'bah continued in the Juraham tribe for a long period.

Ishaq A (Isaac), the younger step-brother of Isma'il A (Ishmael) was also Rasul (Messengers) of Allah (God). Ya'qub A (Jacob), the son of Ishaq A (Isaac) also became a Rasul (Messenger) of Allah (God). Ya'qub A (Jacob) is also known as Isra'il.
A large number of Rusul (Messengers) come from the family of Ishaq A (Isaac) i.e. Yusuf A (Joseph), Musa A (Moses), Dawud A (David), Yahya A (John), Sulayman A (Solomon) and 'Isa A (Jesus) were from his family. This was a reward from Allah's (God) pleasure with his father Ibrahim A (Abraham) for his faithfulness and sacrifices.

Isma'il A (Ishmael) was rewarded with the greatest honor of being the ancestor of the last Rasul (Messengers) of Allah (God), Muhammad S. Descendants of Isma'il A (Ishmael) settled all over Arabia. Quraysh and other Arab tribes were from his family.

All Rusul (Messengers) of Islam, Christianity, and Judaism were from the family of Ibrahim A (Abraham).

Millions of Muslims visit the Ka’bah constructed by Ibrahim A (Abraham) with the help of his elder son Isma'il A (Ishmael), to perform Hajj (Pilgrimage to the Ka'bah) every year in the month of Dhul Hijjah. Muslims also flock to the Ka’bah throughout the year for performing ‘Umrah (Lesser Pilgrimage to the Ka’bah).

Allah (God) has made Hajj (Pilgrimage to the Ka'bah) a Fard (Compulsory) for every Muslim once in their life-time, if they can afford the expenses and the rigors of the journey.

In it are manifest signs (for example), the Maqam (place) of Ibrahim (Abraham); whoever enters it, he attains security. And whosoever enters it, he attains security. And Hajj (pilgrimage to Makkah) to the House (Ka’bah) is a duty that mankind owes to Allah, those who can afford the expenses (for one’s conveyance, provision and residence); and whoever disbelieves [i.e. denies Hajj (pilgrimage to Makkah), then he is a disbeliever of Allah], then Allah stands not in need of the ‘Alamin (mankind, jinn and all that exists).
Surah (Chapter) Al ‘Imran (The Family of ‘Imran) The Qur-an 3:97