These are but a few examples of the teachings of the Quran in which moderation is enjoined. They made it obligatory for all members of the community to enjoin what is right and admonish against what is wrong, without restriction to any particular group or specific individuals. By legislating this conduct, the Quran opens the door wide for its teachings to spread, and breathes in them the spirit of life and continuance. It makes every member of the family and the neighborhood a guide for the rest and a guardian over them; rather, it makes every Muslim a guide and watchman over all other Muslims, to lead them to the straight path and restrain them from committing acts of injustice and corruption. Accordingly, all Muslims are individually obligated to convey the Quranic ordinances and implement them. Can anyone imagine any‌ thing stronger and more effective than this army? Rulers exercise their will over their subjects with the power of their armies, but it is obvious that these armies cannot keep close watch over the subjects in all places and at all times. How great is the difference between the army of Islam and the armies of the rulers!
One of the teachings of the Quran that has been most consequential in uniting
the word of Muslims and consolidating their ranks is the tenet of brotherhood among all classes of Muslims, and the repudiation of all distinctions except those of knowl‌ edge and godliness (taqwa). Thus, the Quran says:

Lo, the Noblest of you, in the sight of God, is the best in conduct (Q. ٤٩:١٣). Say [to them, ٠ Muhammad]: "Are those who know equal with those who know not?" (Q. ٣٩:٩).

The Prophet once said:

Verily, God, the Exalted and Glorious, has honored those who were servile during the Age of Ignorance (pre-Islamic period). Through Islam, God removed the haughtiness of the Age of Ignorance and its vainglorious custom of boasting of kinsfolk and noble descent. Today, all the people, be they white, black, Qurayshite,٢١ Arab or non-Arab, are seen to be descendants of Adam. And, assuredly, God created Adam from clay, and the people most beloved by God on the Day of Resurrection are the most obedient and most godly among them.٢٢

He also said:

The excellence of all learned persons over all other people is similar to my excellence over the lowliest among you.٢٣

Hence, Islam allowed Salman the Persian to advance, through the purity of his faith, to the extent of becoming a member of the Prophets household (ahl al-bayt), whereas it humbled Abu Lahab, the Prophets uncle, for his rejection of faith.
The Prophet of Islam did not pride himself over his people because of his clan,
noble descent, or any of the other things that were generally considered a reason for self-esteem in his time. Rather, he called the people to believe in God and the Day of Resurrection, and to affirm oneness of God and unity among the people. It is forthis reason that he gained power over a community that used to pride itself on noble lin‌ eage with hearts full of dissension and hypocrisy. Consequently, he influenced its character in such a way that he eliminated false pride and arrogance, to the point that a wealthy person of high lineage would give his daughter in marriage to. a poor Muslim, even though [one] of a lowly descent.٢٤