Responsa su Levitico 19:38

For we cannot say that the prohibition on the medium and the wizard derives from, “Before a blind person, do not place an obstacle” (Lev. 19:14), which is Rabbi Yishmael’s position in the chapter Arba Mitot (Sanhedrin 56b), about the Children of Noah [non-Jews], that they are prohibited from magic, since we do not rule in favor of R Yishmael {I think this is actually referring to R Yosi}

As to that, there can be no religious mandate, just as there is no secular mandate. Yet David Hoffman in Melamed L'ho-il, Orah Hayim 42, in discussing the duty to serve in the army, makes clear the fact that it involves Sakana, and Sakana can lead to violation of the Sabbath; nevertheless he indicates that such violation of the Sabbath involving danger is permitted if the journey or the enterprise is for the purpose of fulfilling a mitzvah (based chiefly upon Bes Joseph to Tur Orah Hayim 248). Then he continues that not to serve in the army involves more than the failure to observe a mitzvah but actually a sin of the profanation of the Name because of the effect that such evasion could have on the good name of the Jewish community. With regard to the chaplaincy, both elements are involved. There is certainly the mitzvah of making possible regular worship for the soldiers and also the avoidance of profanation of the Name if too few chaplains would be available. For these two reasons it is permitted to accept Sakana which would lead to violation of the Sabbath. Yet there is a religious duty to keep others from danger and to diminish their peril. He who does not do what he can to save others, violates the command, "Stand not idly by the danger to thy brother" (Lev. 19:16). So Maimonides takes this verse in Hil. Rozeach 1:14. See also Naftali Berlin (Neziv) to Sheeltot Exodus 38, who says that one should strive with all his strength to save another up to the risk of his life.

Regarding cutting sidelocks. Did the Torah forbid this even with the use of scissors? The Torah only says "Do not round off" (Leviticus 19:27), not 'do not destroy.' Is there any sense in the argument to permit this, based on the source in the Tosefta,¹cf. Sifra Kedoshim 6:4, Makkot 21a:6 whereby the laws pertaining to haircutting are juxtaposed to the laws pertaining to beard-shaving, and in both cases, one is not liable unless a razor-blade is used²This argument is rejected by Tosafot on Shevuot 2b:12.

They responded: The Torah declared "Do not destroy the corners of your beard," (Leviticus 19:27) - referring to anything that can destroy. And to the destroyers, go tell them: Where is your King and the Rock of your strength?²cf. Deuteronomy 32:37. A commandment that can be fulfilled so easily, and you have forgotten it?

"My beloved Rabbi Joseph Josel, greetings!
As yet you have given only evasive answers to my letters. You have scolded your friends who reminded you that you left a family behind. You have shown great animosity to those who reprimanded you therefor. But the biblical law (Leviticus 19:17) 'Thou shalt surely rebuke thy neighbor' obliges me to write to you again. Moreover, I could not refrain from seeing the grief, tears, and broken-down condition of your chaste wife. Is she to wait for you all her life? And as far as you are concerned, is this to be the life of a scholar? Furthermore, no scholar is allowed to separate from his wife for more than three years; and may God save you from that! How much blood have you shed, your own and your children's!

After washing the hands in the morning, I say asher yazar. Immediately thereafter I recite Elohai neshamah, leaving the benediction al netilat yadayim to be said at the synagogue. After the benediction of the Torah, I add three verses from the Pentateuch (Leviticus, 19:16-18), three verses from the Prophets (Joshua, 1:7-9), three verses from the Hagiographa (Psalms, 1:1-3), and the Mishnah Elu debarim she-en la-hem shiur (Peah 1:1). Thus I indicate that the benediction of the Torah includes the Mishnah. (The other sections tally with the order of our prayer books.)