Musnad Ahmad 337:4

Surayj ibn al-Nu‘man narrated to us, he said: ‘Abdullah ibn Wahb narrated to us, from ‘Amr ibn al-Harith, from Bakr ibn Suwadah al-Judhami, from Salih ibn Khaywan, from Abu Sahlah al-Sa’ib ibn Khallad, that a man led a people in prayer and spat in the direction of the Qiblah while the Messenger of Allah, peace and blessings of Allah be upon him, was watching. When he finished, the Messenger of Allah, peace and blessings of Allah be upon him, said: "He shall not lead you in prayer." After that, he wanted to lead them in prayer, but they prevented him and informed him of what the Messenger of Allah, peace and blessings of Allah be upon him, had said. He mentioned that to the Messenger of Allah, peace and blessings of Allah be upon him, and he said: "Yes." And I believe he said: "You have offended Allah, the Mighty and Majestic."