פירוש על עבודה זרה 70:3

R. Joshua and R. Eliezer disagree as to whether one may use the sap from an orlah tree, R. Joshua permits and R. Eliezer prohibits. So at first, the Talmud thinks that R. Nahman b. Yitzchak follows R. Eliezer who prohibits all sap. But then the Talmud realizes that if this sap comes from the fruit of an orlah tree, even R. Joshua prohibits it. Thus R. Nahman b. Yitzchak can accord even with R. Joshua (phew!).