תּלמוד אויף שמואל א 16:2

MISHNAH: Samuel was a nazir following the words of Rebbi Nahorai, as it is said: “A shaving knife shall not come on his head¹⁸⁷1S. 1:11..” It is said about Samson “a shaving knife¹⁸⁸Jud. 13:5”, and it is said about Samuel “a shaving knife”. Since “a shaving knife” mentioned for Samson refers to nazir¹⁸⁸Jud. 13:5, so “a shaving knife” mentioned for Samuel refers to nazir. Rebbi Yose said, but fear¹⁸⁹Reading מוֹרָא (root ירא) “fear” for מוֹרָה (root possibly مار) “shaving knife”. is only of flesh and blood! Rebbi Nahorai answered him: Was it not said: “Samuel said, how can I go? Will not Saul hear of it and kill me?¹⁹⁰1S. 16:2.” The fear¹⁹¹In most Mishnah mss., the reading here also is מוֹרָה. of flesh and blood already was on him.

But didn't Rabbi Elazar say: Agents of a mitzvah are not damaged—neither in their going nor in their returning? It was a rickety ladder that is susceptible to damaging, and in any case which is susceptible to damaging we don't rely on a miracle. As it is written, "Shmuel said: How will I go? If Shaul hears he will kill me!" (1 Samuel 16:2).

R. Natan says: this is a commandment, as it is written “Samuel said, ‘How can I go? If Saul hears it he will kill me.” (1 Sm 17:2)