וּמִֽי־הָאִ֞ישׁ אֲשֶׁר־אֵרַ֤שׂ אִשָּׁה֙ וְלֹ֣א לְקָחָ֔הּ יֵלֵ֖ךְ וְיָשֹׁ֣ב לְבֵית֑וֹ פֶּן־יָמוּת֙ בַּמִּלְחָמָ֔ה וְאִ֥ישׁ אַחֵ֖ר יִקָּחֶֽנָּה׃
E qual é o homem que ficou noivo de uma mulher e ainda não a tomou? Que ele vá e retorne para sua casa, para que não morra na batalha e outro homem a tome."
Rashi
פן ימות במלחמה [LET HIM GO AND RETURN] LEST HE DIE IN THE WAR — The meaning is: let him return so that he not die, for if he will not hearken to the words of the priests he deserves death (Sifrei Devarim 194:5).
Ibn Ezra
betrothed a woman, but has not taken her in marriage. This passage indicates that there is such a thing as dying before one’s time. Namely, someone who dies in war dies before his time. Accordingly, David said, “…or he shall descend into battle, and be swept away” [I Samuel 26: 10].
Rabbeinu Bahya
פן ימות במלחמה, “lest he die in battle.” The Torah refers to his premature death. This is clear proof that all the people who die in battle died before the time allocated as their life span at birth. We have still more direct proof of this in Samuel I 26,10: ”or his ‘day’ will come and he will die, or he will go down to battle and will die.”