Why does the Torah repeat "Yad" four times in the course of the three current Pesukim?
Rashi #2: Corresponding to the four things that Achan, who descended from Zerach, took from the Cherem of Yericho - a Babylonian coat, two bars of silver, each weighing 100 Shekalim, and a piece of gold.
Malbim (27): This alludes to four descendents of his on whom Hashem put His hand, to give to them prophecy and Ru'ach ha'Kodesh - Eisan ha'Ezrachi, Heiman, Kalkol and Darda 3 .
Oznayim la'Torah: Just as prior to a person's death, he displays of where he is heading - See Kesuvos, 103), so too, when he is born he displays signs of what he is destined to perform in his lifetime. Hence, Zerach stretched out his hand as a sign that his descendent Achan would take from the Cherem.
Why did Yehudah call the second son 'Zerach'?
Rashi: On account of the sheen of the red thread. 1
Rashbam: Because "Zerach" really means red. 2
QUESTIONS ON RASHI
Rashi writes that the verse hints to four Charamim that Achan contravened. What were they?
Bereishis Rabah (85:14): There were the Cherem of Amalek, of Sichon and Og, of Yericho, and of Kena'ani 1 (some texts - Midyan).
Rashi on the Midrash: The text is 'Midyan'. 'Amalek' is Kena'ani Melech Arad (Rashi Yehoshua 7:20, Matanos Kehunah citing the Yerushalmi). If the text is Kena'ani, 'Amalek' refers to Shemos 17:8-13. Ran (Sanhedrin 43b) - it says in Shmuel (1:15:3) "v'Hikisah Es Amalek v'Hacharamtem." (Also when we fought Amalek, there was a Cherem. - PF)
Maharzu on Bereishis Rabah 85:14: Even though we were permitted to take spoils from Sichon and Og, Achan took idolatry, which is Cherem (Pirkei d'R. Eliezer). We took spoils from Midyan; Achan did not give his share to the officers to divide among the soldiers.
Rashi writes that the verse hints to four Charamim that Achan contravened. In Sanhedrin (43b), the two opinions are that he transgressed three, or five!
Riva (28): Rashi means that he transgressed four [in the days of Moshe 1 ], and five including of Yericho, for which he was caught.
Radak (Yehoshua 7:20), Maharsha (43b): The text in Sanhedrin should say that he transgressed three or four.
Divrei David: Rashi explains like Bereishis Rabah (refer to 38:30:151:1), unlike the opinions in Sanhedrin.
Mizrachi - the verse hints only to those of Moshe, for which he was not punished. Moshav Zekenim - some say that Hashem did not punish for hidden matters before Yisrael crossed the Jordan river. Some say that He never punished for hidden matters; Achan's children knew that he took. Gur Aryeh - we expound four in the days of Moshe, for his sin of Cherem Yericho itself was like four (refer to 38:30:1:2).