How the Holy Prophet (Sallallahu alaihi wa sallam) trained the Companions
Hadhrat Usama (May Allah be well pleased with him) was not so high among the Companions and neither was he the chief of any tribe. In fact, he was the son of Hadhrat Zaid (May Allah be well pleased with him) who was the freed slave of Hadhrat Khadija (May Allah be well pleased with them). Again, Hadhrat Usama (May Allah be well pleased with him) was not of mature age. He was only 17 years old. Every person knows that with the wise, lads of this age have no standing. Still the Holy Prophet (Sallallahu alaihi wa sallam) made him the commander of the army and made elderly Companions like Hadhrat Abu Bakr Siddiq and Hadhrat ‘Umar Farooq (May Allah be well pleased with them), who are also the most superior in the whole Ummah, his subordinates. Can any Muslim criticize the decision of the Holy Prophet (Sallallahu alaihi wa sallam)? When people started objecting to it in those times, it greatly angered the Holy Prophet (Sallallahu alaihi wa sallam).
The objective seems to be that ego and pride should not remain in Muslims. Thus, it is mentioned in Seerat Un Nabawiyya that during his caliphate whenever Hadhrat ‘Umar (May Allah be well pleased with him) would see Hadhrat Usama (May Allah be well pleased with him), he would address him as: Assalaamualaikum! O my chief!
Hadhrat Usama (May Allah be well pleased with him) would protest: O Commander of the Faithful! You address me as such?
Hadhrat ‘Umar would reply: As long as I am alive, I will address you in this manner, because when the Holy Prophet (Sallallahu alaihi wa sallam) passed away, you were my chief.
This decision of the Holy Prophet (Sallallahu alaihi wa sallam) was in a way the foreword of making Hadhrat Abu Bakr Siddiq (May Allah be well pleased with him) the Caliph and all the Companions his subjects, so that no one has any objection to this in spite of Hadhrat ‘Abbas and Hadhrat ‘Ali (May Allah be well pleased with them) being the closest relatives of the Holy Prophet (Sallallahu alaihi wa sallam).
Thus, all the Companions accepted the caliphate of Hadhrat Abu Bakr (May Allah be well pleased with him). Then he and the caliphs after him would appoint anyone they wished as the commander of any army and no one could object to it on the basis of their lineage, etc.
After this, the Companions became entirely free of ego and pride. They all attained the station of servitude (‘Abdiyat), which is considered to be the highest station as per Islamic spirituality (Tasawwuf). There are many Traditions and incidents in the authoritative biographies of the Holy Prophet (Sallallahu alaihi wa sallam) and in canons of history, which support this view.
[Excerpted from Maqasid Ul Islam, Vol. 9]