Christians strive to be exemplary. After receiving Scriptural counsel, a Christian who continues to keep a gun for protection against other humans could not be considered exemplary.
لِذَا لَا تُوكَلُ إِلَيْهِ مَسْؤُولِيَّاتٌ أَوْ تَعْيِينَاتٌ خُصُوصِيَّةٌ فِي ٱلْجَمَاعَةِ .‏