115. The people of Aiykah have been briefly mentioned in verses 78-84 of Surah Al-Hijr. More about them here. There is a difference of opinion among the commentators as to whether the Midianites and the people of Aiykah were two different tribes or one and the same people. One group holds that they were different tribes and gives the argument that in Surah Al-Aaraf Prophet Shuaib (peace be upon him) has been brother of the Midianites (verse 85), whereas here, with regard to the people of Aiykah, he has not been called so. The other group holds that they were one and the same people on the ground that the moral diseases and characteristics mentioned of the Midianites in Surahs Al-Aaraf and Houd are the same as of the people of Aiykah mentioned here. Then the message and admonition of Prophet Shuaib (peace be upon him) to both the tribes was the same, and the two tribes also met the same end.
Research in this regard has shown that both the views are correct. The Midianites and the people of Aiykah were doubtless two different tribes but branches of the same stock. The progeny of Prophet Abraham (peace be upon him) from his wife (or slave girl) Keturah, is well known in Arabia and in the history of the Israelites as the children of Keturah. Their most prominent branch was the one which became famous as the Midianites, after their ancestor, Midian, son of Abraham. They had settled in the territory between northern Arabia and southern Palestine, and along the coasts of the Red Sea and the Gulf of Aqabah. Their capital city was Madyan, which was situated, according to Abul Fida, on the western coast of the Gulf of Aqabah at five days’ journey from Aiykah (present day Aqabah). The rest of the children of Keturah, among whom the Dedanites are comparatively better known, settled in the territory between Taima and Tabuk and Al-Ula in northern Arabia, their main city being Tabuk, the Aiykah of the ancient times. (Yaqut in his Mujam al-Buldan, under Aiykah, writes that this is the old name of Tabuk, and the natives of Tabuk confirm this).
The reason why one and the same Prophet was sent to the Midianites and the people of Aiykah was probably that both the tribes were descendants of the same ancestors, spoke the same language and had settled in the adjoining areas. It is just possible that they lived side by side in the same areas and had marriages and other social relations between them. Then, these two branches were traders by profession and had developed similar evil practices and social and moral weaknesses. According to the early books of the Bible, these people worshiped Baal-peor. When the Children of Israel came out of Egypt and entered their territory, they also became infected with the evils of idolatry and adultery. (Numbers, 25: 1-5, 31: 16-17). Then those people had settled on the two main international trade routes, the one joining Yaman with Syria and the other the Persian Gulf with Egypt. Due to their advantageous position they had started big scale highway robbery and would not let any caravan pass till it had paid heavy taxes. They had thus rendered these trade routes highly unsafe. Their characteristic of highway robbery has been mentioned in the Quran, for which they were admonished through Prophet Shuaib (peace be upon him), thus: And do not lie in ambush by every path (of life) as robbers in order to frighten the people (Surah Al-Aaraf, Ayat 86). These were the reasons why Allah sent to both the tribes the same Prophet, who conveyed to them the same teachings and message. For the details of the story of Prophet Shuaib (peace be upon him) and the Midianites, see (Surah Al-Aaraf, Ayats 85-93); (Surah Houd, Ayats 84-95); and (Surah Al-Ankabut, Ayats 36-37).