Musnad Ahmad 1153:2156

Muhammad ibn Ubayd narrated to us, he said: Al-A’mash narrated to us, from Ibrahim, from Al-Aswad, he said: Some people were wrestling, and the tent rope struck the eye of one of them, so they laughed. Aisha said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "There is no believer who is pricked by a thorn, or anything greater than that, but that Allah removes a sin from him thereby, and raises him a degree thereby."