Musnad Ahmad 28:361

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from 'Amr ibn Murrah, from 'Abdullah ibn al-Harith, from Abu Kathir, from 'Abdullah ibn 'Amr, from the Prophet, peace and blessings of Allah be upon him, who said: "Beware of injustice, for injustice is darknesses on the Day of Resurrection. And beware of obscenity, for Allah does not love obscenity nor the seeking of it. And beware of stinginess, for it destroyed those who were before you; it commanded them to sever ties, so they severed them; and to be miserly, so they were miserly; and to commit immorality, so they committed immorality." He said: A man stood up and said: "O Messenger of Allah, which Islam is best?" He said: "That the Muslims are safe from your tongue and your hand." That man, or another man, said: "O Messenger of Allah, then which migration is best?" He said: "That you migrate from what Allah dislikes. And migration is of two types: the migration of the dweller and the nomad. As for the nomad, he obeys when he is commanded, and he answers when he is called. As for the dweller, he is the greater of the two in trial, and the greater of the two in reward."