Why did she send to Barak?
Tana d'Vei Eliyahu Rabah (10): Barak served Chachamim in Yehoshua's lifetime 1 and after his death. Hashem showed Devorah that the salvation will be via people who engage in Torah constantly every day.
Radak: He was her husband (refer to 4:4:2:2). At the time of her prophecy she separated from him and sat under Tomer Devorah.
If so, he was very old, for between Yehoshua's death and now were at least 140 years! (PF)
Where did Hashem command so?
Rashi (from Mechilta): "Hacharem Tacharimem" (Devarim 20:17).
Tana d'Vei Eliyahu Rabah (10): It says "v'Dirshu ha'Shoftim Heitev" (Devarim 19:18), and shortly after (20:1) "Ki Seitzei la'Milchamah [do not fear...]"
Radak #1: (He commanded so now.) These were not her first words to Barak; the Navi recorded only what is needed. The same applies to "ha'Lo Shamat Biti" (Rus 2:8) and "Ki Nasan Hashem b'Yadeinu Es Kol ha'Aretz" (Yehoshua 2:24 1 ).
Radak #2: He did not command so elsewhere. 2 This was said to strengthen the matter and warn him not to slacken. The same applies to "ha'Lo Shelachticha" (6:14) said to Gid'on].
What is the meaning of "u'Mashachta"?
Radak: Draw Yisrael and entice them verbally, until they will come to Har Tavor. Yisrael were afraid of Sisera's army, therefore they needed enticement and soft words. 1
Verses 4-5 imply that she was an established prophet. If so, her words "u'Nesatihu b'Yadecha" (verse 7) should suffice! However, even Gid'on, who himself had prophecy, requested Simanim that he will win (6:37-39! - PF)
Why did he take from Naftoli and Zevulun?
Tana d'Vei Eliyahu Rabah (10): Naftoli served Yakov, and he was pleased. 1 Zevulun served Yisachar and hosted him. (refer to Devarim 33:18:2:1).
Rashi (Bereishis 49:21): "Naftoli Ayalah Sheluchah" - they went with zealousness to fight against Sisera.
Presumably, we learn from "Naftoli Seva Ratzon" (Devarim 33:23). (PF)
