Musar for Shabbat 101:7
אמר ליה רב נחמן לדרו עבדיה אטמין לי צונן ואייתי לי מיא דאחים קפילא ארמאה שמע רבי אמי ואיקפד אמר רב יוסף מ"ט איקפד כרבוותיה עביד חדא כרב וחדא כשמואל
R. Huna said on Rabbi's authority: Cold [water, food, etc.] may not be hidden.<span class="x" onmousemove="('comment',' To keep it cool. ');"><sup>12</sup></span> But it was taught: Rabbi permitted cold [water, etc.] to be hidden? — There is no difficulty: the one [ruling was given] before he heard it from R. Ishmael son of R. Jose; the other after he heard it [from him]. For Rabbi sat and declared: Cold [water, etc.] may not be hidden. Said R. ishmael son of R. Jose to him, My father permitted cold [water] to be hidden. Then the Elder<span class="x" onmousemove="('comment',' The Sage, referring to R. Jose. ');"><sup>13</sup></span>