It is narrated from Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Do you know who the Muslim is?" The Companions said: "Allah and His Messenger (peace and blessings be upon him) know best." He (peace and blessings be upon him) said: "The one from whose hand and tongue the Muslims are safe."
The Companions said: "Then who is the believer?" He (peace and blessings be upon him) said: "The one from whom the believers feel secure regarding their lives and their wealth."
They said: "Then who is the emigrant (muhajir)?" He (peace and blessings be upon him) said: "The one who abandons evil and keeps away from it."
Hadith Referenceالمعجم الأوسط / باب الباء / 3188
Hadith Takhrij«أخرجه أحمد فى «مسنده» برقم: 7044، 7138، وعبد بن حميد فى «مسنده» برقم: 336، والطبراني فى «الكبير» برقم: 14610، 14611، والطبراني فى «الأوسط» برقم: 232»