Deuteronomy20chapter 20

Ramban on Deuteronomy 20:1

WHEN THOU GOEST FORTH TO BATTLE AGAINST THINE ENEMIES, AND SEEST HORSES, AND CHARIOTS etc. This is a new commandment which he now declared to them as they came into battles.

Read it in full at Sefaria · Commentary on the Torah by Ramban (Nachmanides). Translated and annotated by Charles B. Chavel. New York, Shilo Pub. House, 1971-1976

Onkelos Deuteronomy 20:10

When you near a city to do battle against it, you are to offer it [ words of ] peace.

Read it in full at Sefaria · Metsudah Chumash, Metsudah Publications, 2009 [with Onkelos translation]

Ramban on Deuteronomy 20:11

“[Their surrender is not to be accepted] until they accept tribute and servitude upon themselves.” This is the language of Rabbeinu Shlomo [Rashi]. And in the Sifre the Rabbis have said: 340 Sifre, Shoftim.

Read it in full at Sefaria · Commentary on the Torah by Ramban (Nachmanides). Translated and annotated by Charles B. Chavel. New York, Shilo Pub. House, 1971-1976

Rashi on Deuteronomy 20:14

והטף AND THE LITTLE ONES [… SHALT THOU TAKE UNTO THYSELF] — the male children, too. But how am I to understand (v. 13) “and thou shalt smite every male thereof”? As referring to the male adults (Sifrei Devarim:7).

Read it in full at Sefaria · Pentateuch with Rashi's commentary by M. Rosenbaum and A.M. Silbermann, 1929-1934