Inna Allaha istafa adama wanoohan waala ibraheema waala AAimrana AAala alAAalameen (surah Al Imran: 33)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(3:33) Truly Allah *29 chose Adam and Noah and the descendants of Abraham and of 'Imran *30 above all mankind.

Innal laahas tafaaa Aadama wa Noohanw wa Aala Ibraaheema wa Aala Imraana `alal `aalameen

*29). This marks the beginning of the second discourse. The period of its revelation is about 9 A.H., when a delegation from the Christian republic of Najran visited the Prophet. Najran lies between the Hijaz and Yaman, and comprised, at that time, seventy-three towns and villages. Its population can be gauged from the fact that an estimated one hundred and twenty thousand men could bear arms. The entire population was Christian and was under the hegemony of three Christian chiefs. The first of these, 'aqib, was the head of the community. The second, sayyid, looked after the collective and political affairs of the people. The third, usquf (bishop), was their religious leader. (See Ibn Hisham, vol. 1, p. 573; Ibn Ishaq, Life of Muhammad, tr. A. Guillaume, pp. 270 f. - Ed.)
When the Prophet annexed Makka, the whole of Arabia became convinced that the future of the area was bound up with him, and deputations from all parts of the peninsula began to visit him. In this connection the three chiefs of Najran came to Madina accompanied by sixty people. As they were not prepared to go to war, the alternatives before them were either to embrace Islam or to live as dhimmis (protected non-Muslim subjects of the Islamic state). It was on this occasion that God revealed this discourse; it served as an invitation to the people of Najran to accept Islam.
*30). 'Imran was the father of Moses and Aaron, and has been mentioned in the Bible as Amram.