Musnad Ahmad 28:330

Yahya ibn Sa'id narrated to us, from Isma'il, who said: 'Amir informed me, saying: A man came to 'Abdullah ibn 'Amr while people were with him, and he stepped over them [to reach him]. They prevented him, but he [‘Abdullah] said: "Leave him." So he came until he sat beside him, and said: "Inform me of something you memorized from the Messenger of Allah, may Allah bless him and grant him peace." He said: "I heard the Messenger of Allah, may Allah bless him and grant him peace, say: 'The Muslim is the one from whose tongue and hand the Muslims are safe, and the emigrant (Muhajir) is the one who abandons what Allah has forbidden.'"