The Death of Rabbi Akiva -- Talmud Berakhot 61b
When Rabbi Akiba was taken out to be executed, it was the hour for recital of the Shema, and the executioners were combing his flesh with iron combs, while he was lovingly making ready to accept upon himself the yoke of the kingship of Heaven. His disciples asked: Our teacher, even to such a degree? He replied: All my days I have been troubled by this verse "With all thy soul" (Deut. 6:5), which I have interpreted meaning "Even if (God) takes your soul." But I said: When shall I have an occasion to fulfill the precept? Now that I have an occasion, shall I not fulfill it? He prolonged the Shema's concluding word, echad, ("one"), until he expired as he finished pronouncing it. A divine voice went forth and proclaimed: Happy are you, Akiva, that your soul departed with the word echad!
(ג) בית שמאי אומרים, בערב כל אדם יטו ויקראו, ובבקר יעמדו, שנאמר "ובשכבך ובקומך" (דברים ו, ז). ובית הלל אומרים, כל אדם קורא כדרכו, שנאמר "ובלכתך בדרך" (שם). אם כן, למה נאמר ובשכבך ובקומך, בשעה שבני אדם שוכבים, ובשעה שבני אדם עומדים. אמר רבי טרפון, אני הייתי בא בדרך, והטיתי לקרות, כדברי בית שמאי, וסכנתי בעצמי מפני הלסטים. אמרו לו, כדי היית לחוב בעצמך, שעברת על דברי בית הלל.
(3) The school of Shammai says: In the evening all people should recline and recite [Shema], and in the morning they should stand, since it says [in the verse (Deut. 6:7)], “And when you lie down and when you arise.” But the school of Hillel says: Each person may recite it in his usual way (posture), since it says (ibid.), “And when you walk on the road.” If so, why does it say “and when you lie down and when you arise”? —[It means:] at the time when people are lying down, and at the time when people are arising. Said Rabbi Tarfon: “I was once traveling on the road, and I reclined to recite [Shema] in accordance with the view of the school of Shammai, and [by doing so] I put myself in danger of [attack by] bandits.” They [the other Sages] said to him: “You would have deserved to be guilty for your own fate, since you went against the view of the school of Hillel.”