But about this and about that, R' Yehoshua said: This is not terumah concerning which I am warned against contaminating it, only [terumah which I am commanded to withhold] from eating it. What is the case where there is a prohibition on contami-nating it? [If] he was going from place to place, and [there were] loaves of terumah in his hand. An idolater said to him: “Give [me] one of them and I will contaminate [only] it; if not, I will contaminate all of them.” R' Eliezer says: [Let the idolater] con-taminate all of them, but he must not give him one of them [to] contaminate. R' Yehoshua says: He places one in front of him on the rock.