וַיֹּ֥אמֶר הַנָּחָ֖שׁ אֶל־הָֽאִשָּׁ֑ה לֹֽא־מ֖וֹת תְּמֻתֽוּן׃
(Gen. 3:4, MT)
Note this is normal Hebrew syntax. A word for word translation does not convey the literal meaning of the expression. "You will not actually die."
“You are not going to die,..."
(Genesis 3:4, Jewish Publication Society, Tanakh 1985)
And the serpent said to the woman: You will not die at all. Instead God knows that on the day you eat from it your eyes will be opened, and you will be like God and know what good and evil is.
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Bonhoeffer, D. (2004). Creation and Fall: A Theological Exposition of Genesis 1–3 (M. Rüter, I. Tödt, & J. W. de Gruchy, Eds.; D. S. Bax, Trans.; Vol. 3, p. 111). Fortress Press.
„Ihr werdet nicht alsobald sterben. Gott weiß es recht wohl, an dem Tage, an welchem ihr davon esset, werden euch die Augen aufgehen, werdet ihr gleich Gott sein, wissend, was gut ist und böse ist.“ -- Kroeker, J. (1926). Die erste Schöpfung, ihr Fall und ihre Wiederherstellung: Genesis 1–3 (Vol. 1, p. 279). Missionsverlag „Licht im Osten“.
§ 86. Use along with its own verb. — (a) When before its verb the kind of emphasis given by inf. abs. may be of various kinds, e.g. that of strong asseveration in promises or threats; that of antithesis in adversative statements; the emphasis natural in a supposition or concession; and that of interrogation, particularly when the speaker is animated, and throws into the question an intonation of surprise, scorn, dislike, &c. Such shades cannot be reproduced in translation. Occasionally such a word as indeed, surely (Gen. 2:17), forsooth (37:8), of course (43:7), at all (Hos. 1:6), &c., may bring out the sense, but oftenest the kind of emphasis is best expressed by an intonation of the voice.
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Davidson, A. B. (1902). Introductory Hebrew grammar Hebrew syntax (3d ed., p. 117). T&T Clark.
(b) In negative sent. inf. abs. precedes the neg. Is. 30:19 בָּכוֹ לֹא־תִבְכֶּה thou shalt not weep. Jud. 15:13 above, Ex. 8:24; 34:7, Deu. 21:14, Jud. 1:28, 1 K. 3:27; Am. 3:5; Jer. 6:15; 13:12. With אַל, 1 K. 3:26, Mic. 1:10. Exceptions occur mostly when a denial is given to previous words, Gen. 3:4, Am. 9:8, Ps. 49:8.
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Ibid., p. 118.