Warabbuka aAAlamu biman fee assamawati wal-ardi walaqad faddalna baAAda annabiyyeena AAala baAAdin (surah Al Isra: 55)

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

(17:55) Your Lord is fully aware of all the creatures in the heavens and the earth. We have exalted some Prophets above the others in ranks, *62 and We gave the Psalms to David. *63

Wa Rabbuka a`lamu biman fis samaawaati wal lard; wa laqad faddalnaa ba`dan Nabiyyeena `alaa ba`dinw wa aatainaaa Daawooda Zabooraa

*62) Though this has apparently been addressed to the Holy Prophet, in fact the real addressees arc the disbelievers of Makkah. This is to rebuke them for the low opinion they held in regard to the Holy Prophet. As it commonly happens contemporaries, in general, and opponents, in particular, do not see anything great and noble in a person of their own time. The same was the case with the contemporaries of the Holy Prophet who could not see anything extraordinary or great in him. He appeared to be merely a common man of their habitation. On the other hand, they were full of praise in regard to the famous personalities who had lived in the past few centuries and imagined them to be the perfection of greatness. That is why, they raised frivolous objections against his claim to Prophethood, as if to say, "Look at this man who considers himself to be a Prophet whereas he cannot stand in comparison with the former great Prophets who are held in high esteem by all. " Allah has answered their objection, as if to say, "We are fully aware of all Our creatures in the heavens and the earth, and We know their ranks but you do not know. We know whom to favour with Prophethood, as We have been favouring the former Prophets and exalting some Prophets above others in rank."
*63) It appears that Prophet David has been particularly mentioned to show that Prophethood dces pot mean that one should have nothing to do with the life of this world. This was the answer to the objection they were raising against the claim to Prophethood by Muhammad (Allah's peace be upon him), that he was a man of the world. It means to say, "Though David was a king who had to engage himself in worldly affairs more than a common man, he was favoured by Allah with Prophethood, and given the Book, the Psalms. Likewise Muhammad (Allah's peace be upon him) could be favoured with Prophethood inspite of the fact that he had wife and children and passed his life like other common people and was ' engaged in buying and selling in the market, in short, in performing all those duties that a man of the world has to perform to meet his necessities of life. This was necessitated because according to the disbelievers of Makkah, such a man of the world could not be considered to be even a pious man, much less a Prophet, for pious people should have nothing to do with the worldly affairs but should sit in seclusion and remember God whereas the Holy Prophet had to work to fulfil the necessities of life.