Translation of the verse 28 from Surah Saba’ : Number of verses 54 - - page 431 - Part 22.
And We have not sent you (O Muhammad SAW) except as a giver of glad tidings and a warner to all mankind, but most of men know not.
And We have not sent you except comprehensively to mankind as a bringer of good tidings and a warner. But most of the people do not know.
(34:28) (O Prophet), We have not sent you forth but as a herald of good news and a warner for all mankind. But most people do not know. *47
*47) That is, "You have not been sent as a Prophet for the people of this city, or this country, or this age alone, but for the people of the entire world and for ever, but your compatriots do not recognize your worth and they do not realize how great a person has been raised among them as a Prophet and how uniquely they have been blessed by Allah."
The fact that the Holy Prophet has not been appointed a Prophet only for his own country or for his own age but for all mankind till Resurrection, has been stated at several places in the Qur'an. For instance,
"And this Qur'an has been revealed to me that I should thereby warn you and all those whom it may reach." (AI-An'am: 19).
"O Prophet, say: O mankind, I am a Messenger to all of you from Allah. " (Al-A'raf: 158).
"O Prophet, We have sent you to be a real blessing for all the people of the world. " (Al-Anbiya' : 107) .
"Highly blessed is He Who has sent down Al-Furqan to His servant so that he may be a warner to all mankind." (Al-Furqan: 1).
The same thing has been stated by the Holy Prophet in a number of Ahadith in different ways. For example.
"I have been sent to all mankind, the black as well as the white." (Musnad Ahmad: Marwiyat Abu Musa Ash ari).
"I have been sent to alI mankind as a whole, whereas cvery Prophet before me was only sent to his own people." (Musnad Ahmad: Marwiyat 'Abdullah bin 'Amr bin 'As). "Before me cvery Prophet was specifically sent to his own people; but I have been sent for all mankind. " (Bukhari and Muslim: From Traditions related by Jabir bin 'Abdullah).
"My appointment as d Prophet and Resurrection are like this. Saying this the Holy Prophet raised his two fingers." (Bukhari and Muslim). What he meant by this was : "Just as no third finger intervenes between these two fingers, so there is no prophethood between the and Resurrection. After me there will be Resurrection only, and I shall be the Prophet till Resurrectian."