Kommentar zu Bereschit 19:18

אל נא אדני OH NOT SO, MY LORD — Our Rabbis said, that this name (Lord) is holy (i. e. refers to God; Shevuot 35b), since it is said regarding him (i.e. regarding the one who was addressed by this name) (v. 19) “[and thou hast magnified thy mercy …] in keeping alive my soul”. Therefore it must refer to Him who has the power to kill or keep alive. Indeed the Targum renders it, “I beg of thee, O Lord)”

ויאמר...אל נא, he begged them not to make him rush up the mountain as he was physically unable to move so quickly.

Our Sages said that this Name is holy. In light of this we must understand Rashi’s next comments: אַל נָא אל תאמרו אלי וכו', נָא לשון בקשה. Rashi is saying that this verse is split delicately into two parts. Lot says to the angels [only one word]: אַל. By this, Lot conveys: “Do not tell me to flee to the mountain.” Then begins his prayer to Hashem: נָא ה', הנה מצא עבדך. And this is what Rashi means by, “נָא. It has the meaning of making a request.” In other words, Lot’s request to Hashem begins with the word נָא, as Rashi said before: “The Targum also translates it בבעו כען ה'.” I.e., בבעו is the translation of נָא, and expresses a request. This is why Rashi first explains that this Name is holy, and only then explains אַל נָא, contrary to the verse’s order. Rashi is telling us that since our Sages said this Name is holy, we must separate אַל from נָא. And אַל means: “[O angels,] do not tell me to flee to the mountain,” while נָא begins Lot’s prayer to Hashem. (R. Meir Stern)