Musnad Ahmad 5:660

Abdullah narrated to us, Ishaq bin Isma'il narrated to us, Jarir and Muhammad bin Fudayl bin Ghazwan narrated to us, from Mutarrif, from Abu Ishaq, from 'Asim bin Damrah, from 'Ali, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) would not perform a prayer that had a prayer after it, except that he would perform two rak'ahs after it."