Halakha Ulangan 20:7: Mishneh Torah, Human Dispositions, Mishneh Torah, Kings and Wars & Arukh HaShulchan

The way of sensible people: A man should first select a permanent vocation out of which to derive a livelihood, then buy a home, and after that take unto himself a wife, as it is said: "And what man is there that built a new house and hath not dedicated it, And what man is there that hath planted a vineyard, and hath not used the fruit thereof, And what man is there that hath betrothed a wife and hath not taken her". (Deut. 20.5–7).¹⁴The Hebrew text quotes “And what man is there that hath planted a vineyard” first, which is an evident error; Maimonides only emphasizes that marriage should take place only after attaining an established livelihood. G. But fools reverse it by taking a wife first, and after that, if he be able, purchase a home, and after that, in his declining years, he will turn about looking for a vocation, or be supported on charity. Even so is it reversed when pronouncing adversity: "Thou shalt betroth a wife, thou shalt build a house, thou shalt plant a vineyard" (Deut. 28.30), meaning, thy actions shall be reverse so that thou be unsuccessful in thy ways. But of a blessing it is said: "And David acted wisely in all his ways, and the Lord was with him" (First Samuel. 18.14).¹⁵See Pesahim, 50, about one who is supported by his wife’s earnings. G.

At the time they are organizing to deploy in their battle array and are ready to do battle, the Anointed for War stands on a high place with the entire army before him and says to them in the Holy Tongue, “Shema Yisroel, you are about to do battle today with your enemies. Have no fear in your hearts, do not be frightened, do not scurry about and do not flee from before them. HaShem, your G-d, goes with you to fight with your enemies and save you” (Deut. 20:3-4). Until here does the Anointed for War speak. A subordinate Kohen now broadcasts this message to the people in a loud voice. The Anointed for War again speaks and says, “Is there a man here who has built a new home and has not dedicated it? Let him go and return to his house lest he die in battle and another man dedicate it. Is there a man here who has planted a vineyard and has not used its fruit? Let him go and return to his house lest he die in battle and another man use its fruit. Is there a man here who has betrothed a wife and has not taken her? Let him go and return to his house lest he die in the battle and another man take her” (Deut. 20:5-7). Until here does the Anointed for War speak. Then a⁵⁵Lit., the. marshal broadcasts this message to the people in a loud voice. The marshal himself then speaks and says, “Is there a man here who is afraid and weak of heart?” (Deut. 20:8). Another officer then broadcasts this to the people.

In my humble opinion, the Halakhic authorities do not differ at all, for behold, it is true that the word “ḥupah” is not written in the Torah, only the word (for) marriage, as it is written: “(In the case of) one who betrothes a woman but has not (yet) taken her…”
[illegible] marriage, since, according to Torah law proper, when he has intercourse with her for the sake of marriage, she is (considered) his wife completely and she is (considered) married. So wrote the Rambam.
However, it is not the way for Israelites to have this intercourse in public, and therefore, we would require witnesses to the “yiḥud” for intercourse. And even if it was possible that there was no need for witnesses to this (“yiḥud”), as it is written in paragraph 5, in every instance the matter would be in public (in reality) - for behold, (we) must bless them with the seven benedictions immediately before the marriage (ceremony). Therefore, our rabbis, may their memories be for a blessing, established that the “ḥupah” will be (can be) in place of the “nisuin” (i.e. the two terms can be used synonymously). It has always been this way; even in the time of the prophets, as it is written: “like a groom going out from his ‘ḥupah’ ” (Psalm 19:6), and, it says: “and a bride from her ‘ḥupah’ ” (Joel 2:16). (Cf. VIII) Obviously (then), thus did Moses our Rabbi instruct (lead) Israel.