Khatam an-Nabiyyin

Khatam an-Nabiyyin (Arabic خاتم النبيين‎) or Khātim an-Nabīyīn, is a title used in the Quran to designate the prophet Muhammad and it is also translated as The Best and The Most Perfect of all Prophets.

Quran
مَّا كَانَ مُحَمَّدٌ أَبَآ أَحَدٍ مِّن رِّجَالِكُمْ وَلَـٰكِن رَّسُولَ ٱللَّـهِ وَخَاتَمَ ٱلنَّبِيِّـۧنَ وَكَانَ ٱللَّـهُ بِكُلِّ شَىْءٍ عَلِيمًا
 * Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets: and Allah has full knowledge of all things."
 * Qur'an - Chapter 33 Verse 40

Hadith

 * My similitude in comparison with the prophets before me is that of a man who has built a house nicely and beautifully, except for a place of one brick in a corner. The people go about it and wonder at its beauty, but say: 'Would that this brick be put in its place!' So I am that brick, and I am the seal of the prophets"
 * Sahih al-Bukhari, Kitab ul Manaqib, Haidth No. 44, Sahih Muslim: Kitab al-Fada'il, Hadith No. 24
 * On the day of judgment, when people will ask the Prophet to intercede, they will say: "O Muhammad, you are the Messenger of Allah and the Last Prophet."
 * Sahih al-Bukhari, Hadith No. 4712, Sahih Muslim: Hadith No. 194