(6) باب إِثْمِ مَنْ آوَى مُحْدِثًا
Narrated `Asim:
I said to Anas, "Did Allah's Messenger (ﷺ) make Medina a sanctuary?" He replied, "Yes, (Medina is a sanctuary from such-and-such place to such-and-such place. It is forbidden to cut its trees, and whoever innovates an heresy in it or commits a sin therein, will incur the curse of Allah, the angels, and all the people." Then Musa bin Anas told me that Anas added, "..... or gives refuge to such an heretic or a sinner..."
Reference: Sahih al-Bukhari 7306
In-book reference: Book 96, Hadith 37
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 92, Hadith 409