Why was Tuval Kayim called by that name?
Rashi: Because he improved the occupation of Kayin (the murderer) by inventing weapons for murderers that kill - ?Tuval? is a Lashon of ?Tevel? - preparing.
What are the connotations of ?Loteish Kol Choreish Nechoshes u?Barzel??
Rashi: It means ?who polished (or sharpened) all culling implements of copper and iron?.
Targum Onkelos and Targum Yonasan: The Torah means that he was the founder of all copper and iron- smiths.
The Torah informs us that Tuval Kayin's sister was called Na'amah. Who was Na'amah?
Rashi and Ramban #1 (citing a Midrash): She later married Noach. 1 The Ramban adds that she was called 'Na'amah' on account of her beautiful deeds, for which she was renowned throughout the world. She was a Tzadekes who had righteous sons. 2
Ramban #2 (citing another Midrash): She was exceptionally beautiful (as her name suggests). In fact, she is the woman hinted later (in Bereishis 6:2), whom the "B'nei ha'Elohim" saw and took.
Ramban #3 (citing the Zohar): She was the mother of Shamdon, the mother of Ashmodai (king of the demons), from whom all the demons descended.
Gur Aryeh: How does Rashi know this? Out of the multitude of women, why is specifically Na'amah mentioned? This verse must be coming to explain to us in what merit Noach's wife survived the Flood. She was righteous in her own right, and her ways were 'pleasant,' as her name Na'amah implies.
In which case, Kayin did leave behind something of a legacy.
Why does it say, "also" Tzilah gave birth?
Hadar Zekenim, Rosh (to 4:23); Gur Aryeh (to 4:19): Rashi (to 4:19) explained that Lemech had given her a sterility potion. It did not work, and also she gave birth.
QUESTIONS ON RASHI
Rashi writes: "'Polisher of every crafter (Choreish) of copper and iron' - ... [The word] 'Choreish' is in Po-eil form, with the vowel [Tzeirei]." What does Rashi mean?
Gur Aryeh: "Choreish" does not mean [that Tuval-Kayin would polish] the output of the metalsmith's work; for then the first syllable would be accented, and the Reish would have the vowel Segol (Cho-resh). 1 Cho-reish is a verb; Tuval-Kayin would polish the craftsmen's tools which produced that output. 2
