The Prophet ﷺ said, "Medina is a sanctuary from that place to that. Its trees should not be cut and no heresy should be innovated nor any sin should be committed in it, and whoever innovates in it an heresy or commits sins (bad deeds), then he will incur the curse of Allah, the angels, and all the people." (See Hadith No. 409, Vol 9).  

عَنِ النَّبِيِّ ﷺ قَالَ الْمَدِينَةُ حَرَمٌ مِنْ كَذَا إِلَى كَذَا لاَ يُقْطَعُ شَجَرُهَا وَلاَ يُحْدَثُ فِيهَا حَدَثٌ مَنْ أَحْدَثَ حَدَثًا فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ  

The Prophet ﷺ came to Medina and ordered a mosque to be built and said, "O Bani Najjar! Suggest to me the price (of your land)." They said, "We do not want its price except from Allah" (i.e. they wished for a reward from Allah for giving up their land freely). So, the Prophet ﷺ ordered the graves of the pagans to be dug out and the land to be leveled, and the date-palm trees to be cut down. The cut datepalms were fixed in the direction of the Qibla of the mosque.  

عَنْ أَنَسٍ ؓ قَدِمَ النَّبِيُّ ﷺ الْمَدِينَةَ فَأَمَرَ بِبِنَاءِ الْمَسْجِدِ فَقَالَ يَا بَنِي النَّجَّارِ ثَامِنُونِي فَقَالُوا لاَ نَطْلُبُ ثَمَنَهُ إِلاَّ إِلَى اللَّهِ فَأَمَرَ بِقُبُورِ الْمُشْرِكِينَ فَنُبِشَتْ ثُمَّ بِالْخِرَبِ فَسُوِّيَتْ وَبِالنَّخْلِ فَقُطِعَ فَصَفُّوا النَّخْلَ قِبْلَةَ الْمَسْجِدِ  

The Prophet ﷺ said, "I have made Medina a sanctuary between its two (Harrat) mountains." The Prophet ﷺ went to the tribe of Bani Haritha and said (to them), "I see that you have gone out of the sanctuary," but looking around, he added, "No, you are inside the sanctuary."  

أَنَّ النَّبِيَّ ﷺ قَالَ حُرِّمَ مَا بَيْنَ لاَبَتَىِ الْمَدِينَةِ عَلَى لِسَانِي قَالَ وَأَتَى النَّبِيُّ ﷺ بَنِي حَارِثَةَ فَقَالَ أَرَاكُمْ يَا بَنِي حَارِثَةَ قَدْ خَرَجْتُمْ مِنَ الْحَرَمِ ثُمَّ الْتَفَتَ فَقَالَ بَلْ أَنْتُمْ فِيهِ  

We have nothing except the Book of Allah and this written paper from the Prophet (wherein is written:) Medina is a sanctuary from the 'Air Mountain to such and such a place, and whoever innovates in it an heresy or commits a sin, or gives shelter to such an innovator in it will incur the curse of Allah, the angels, and all the people, none of his compulsory or optional good deeds of worship will be accepted. And the asylum (of protection) granted by any Muslim is to be secured (respected) by all the other Muslims; and whoever betrays a Muslim in this respect incurs the curse of Allah, the angels, and all the people, and none of his compulsory or optional good deeds of worship will be accepted, and whoever (freed slave) befriends (take as masters) other than his manumitters without their permission incurs the curse of Allah, the angels, and all the people, and none of his compulsory or optional good deeds of worship will be accepted.  

مَا عِنْدَنَا شَىْءٌ إِلاَّ كِتَابُ اللَّهِ وَهَذِهِ الصَّحِيفَةُ عَنِ النَّبِيِّ ﷺ الْمَدِينَةُ حَرَمٌ مَا بَيْنَ عَائِرٍ إِلَى كَذَا مَنْ أَحْدَثَ فِيهَا حَدَثًا أَوْ آوَى مُحْدِثًا فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ لاَ يُقْبَلُ مِنْهُ صَرْفٌ وَلاَ عَدْلٌ وَقَالَ ذِمَّةُ الْمُسْلِمِينَ وَاحِدَةٌ فَمَنْ أَخْفَرَ مُسْلِمًا فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ لاَ يُقْبَلُ مِنْهُ صَرْفٌ وَلاَ عَدْلٌ وَمَنْ تَوَلَّى قَوْمًا بِغَيْرِ إِذْنِ مَوَالِيهِ فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ لاَ يُقْبَلُ مِنْهُ صَرْفٌ وَلاَ عَدْلٌ