An-Nahl - 16:82

فَإِن تَوَلَّوْاْ فَإِنَّمَا عَلَيْكَ الْبَلاَغُ الْمُبِينُ
[16:82]
But if they turn back, then on you devolves only the clear deliverance (of the message).
But if they turn away, thy duty is only to preach the clear Message.
Then, if they turn away, thy duty (O Muhammad) is but plain conveyance (of the message).