Reference for Shabbat 241:5
ת"ר מעשה ונפלה דליקה בחצירו של יוסף בן סימאי בשיחין ובאו אנשי גיסטרא של ציפורי לכבות מפני שאפטרופוס של מלך היה ולא הניחן מפני כבוד השבת ונעשה לו נס וירדו גשמים וכיבו לערב שיגר לכל אחד מהן שתי סלעין ולאפרכוס שבהן חמשים וכששמעו חכמים בדבר אמרו לא היה צריך לכך שהרי שנינו נכרי שבא לכבות אין אומרים לו כבה ואל תכבה:
BECAUSE HIS RESTING IS OUR OBLIGATION. <b><i>GEMARA</i></b>. R. Ammi said: In the case of a conflagration they [the Rabbis] permitted one to announce, 'Whoever extinguishes [it] will not lose [thereby].' Shall we say that this supports him: IF A GENTILE COMES TO EXTINGUISH, WE DO NOT SAY TO HIM, EXTINGUISH OR DO NOT EXTINGUISH, BECAUSE HIS RESTING IS NOT OUR OBLIGATION: thus we [merely] may not say to him, Extinguish [it],' but we may say, 'Whoever extinguishes [it] will not lose [thereby].' Then consider the second clause: WE DO NOT SAY TO HIM … DO NOT EXTINGUISH but neither may we say to him, 'Whoever extinguishes [it] will not lose [thereby]?'<span class="x" onmousemove="('comment',' For the second clause merely states that it is unnecessary to stop him, which implies, however, that one must not give him a hint to extinguish. ');"><sup>12</sup></span> Rather no deduction can be made from this.<span class="x" onmousemove="('comment',' For one clause of the Mishnah must be exact, even in respect of its implication, whereas the other clause is not to be stressed so far, and it is not known which is exact. ');"><sup>13</sup></span>