Musannaf Ibn Abi Shayba 13:1806

Abu Bakr narrated to us, he said: Ibn Mushir narrated to us, from Isma'il, who said: I said to al-Sha'bi, "Which of the two opinions is more pleasing to you?" He said, "The opinion of Masruq is the more pleasing of the two to me regarding legal rulings (fatwa), and the opinion of Shurayh is the more pleasing of the two to me regarding judicial decisions (qada)."