This is the section from the 'Last Sermon' of Prophet(saw):
"O People, no prophet or apostle will come after me, and no new faith will be born. Reason well, therefore, O people, and understand words which I convey to you. I leave behind me two things, the Quran and my example, the Sunnah, and if you follow these you will never go astray.
All those who listen to me shall pass on my words to others and those to others again; and it may be that the last ones understand my words better than those who listen to me directly. Be my witness, O God, that I have conveyed your message to your people."
Thus the beloved Prophet completed his Final Sermon, and upon it, near the summit of Arafat, the revelation came down:
*"…This day have I perfected your religion for you, completed My Grace upon you, and have chosen Islam for you as your religion…" (Quran 5:3)*