Musnad Ahmad 788:118

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Salih, from al-Sha‘bi, from Abu Burdah, from Abu Musa, from the Prophet, peace and blessings of Allah be upon him, who said: "Three will be given their rewards twice: A man who had a slave woman, so he disciplined her and perfected her discipline, and taught her and perfected her teaching, then he emancipated her and married her. And a slave who fulfilled the right of his Lord, Mighty and Majestic is He, and the right of his masters. And a man who believed in his Book and in Muhammad, peace and blessings of Allah be upon him." He said: Al-Sha‘bi said to me, "Take it for nothing; even if you traveled to Kirman for it, that would be easy."