QUESTION: The Mishnah relates that Shimshon sinned with his eyes when he was lured by the beauty of a foreign woman and married her. How is it possible that a Tzadik like Shimshon, who was the leading Shofet (judge) of Yisrael of his time and who "judged the people of Yisrael like their Father in heaven [judges them]" (10a), could have committed such a sin?
ANSWER: The RAMBAM (Hilchos Isurei Bi'ah 13:14-16) asks this question, and he explains that Shimshon did not sin when he married the foreign woman because he converted her before he married her. Why, then, did his parents protest the marriage, and why does the Mishnah chastise him?
The Rambam explains that the conversion was not performed by a properly ordained Beis Din. A proper Beis Din would not have converted her without first investigating whether there were ulterior motives for the conversion. Shimshon, however, converted the women in the presence of a Beis Din Shel Hedyotos (a Beis Din of uneducated judges), and the women converted only in order to marry him. Therefore, they remained prohibited to him after their conversion. The Rambam adds that their true, ulterior motives became clear later. Since they never genuinely accepted the Mitzvos, their conversion was not considered valid.
Why did Shimshon attempt to convert these women as acceptable Gerim when their conversion was dubious? The commentators (see KEREN ORAH) explain that in order to bring the world to its final state of Tikun, the nations of the world must all come to the recognition of the role of the Jewish people, and the Jewish people's closeness to Hash-m, and they must attempt to humble and attach themselves to the Jewish people. Shimshon -- who judged the Jewish people "k'Echad" (Bereishis 49:16), like Hash-m Who is One, as the Gemara says, and who judged them in the manner of David ha'Melech (as Rashi there writes) -- had the potential to bring about the final Ge'ulah. In order to accomplish this, however, Shimshon knew that he would have to subjugate the nations to Klal Yisrael, and that is what he attempted to do when he took these wives from foreign nations. David ha'Melech had a similar intent when he married women ("Eshes Yefas To'ar") taken during the wars he fought (see Sanhedrin 21b). This was also the intention of Shlomo ha'Melech when he married the daughter of Pharaoh and the other foreign wives whom he converted.
Although Mashi'ach will come from the tribe of Yehudah and from the House of David (as Yakov Avinu alluded to in his blessing to Yehudah), the tribe of Dan always has a part in the Tikun together with Yehudah, and thus Shimshon, from the tribe of Dan, sought to take part in bringing the Mashi'ach. This joint effort is evident in the construction of the Mishkan, which was supervised by Betzalel (from Yehudah) together with Ohali'av (from Dan). Similarly, the Beis ha'Mikdash was built by Shlomo ha'Melech (from Yehudah) with Chiram (maternally from Dan; see Divrei ha'Yamim II 2:13, and Radak to Melachim I 7:14).
This is also implied by the fact that both Yehudah (in Yakov's blessing) and Dan (in Moshe's blessing) are compared to "Gur Aryeh," a lion. The Beis ha'Mikdash (Midos 4:7) and Hashra'as ha'Shechinah in general (Hoshea 11:10; Amos 3:8) are compared to the power of a lion. (The Yetzer ha'Ra of Avodah Zarah that directly opposes the worship of Hash-m in the Beis ha'Mikdash is also represented by a lion; see Sanhedrin 64a. This may be alluded to by Shimshon's act of tearing apart a lion with his hands, after which a beehive filled with sweet honey formed in its carcass. Shimshon sought to destroy the Avodah Zarah in the nation and to replace it with the worship of Hash-m.)
The Midrash (Shemos Rabah 40; Tanchuma, Ki Tisa 13) teaches that Yehudah is the most spiritually uplifted of the tribes while Dan is the least. To build the Beis ha'Mikdash the two must work together, in order to include all of the elements of the Jewish people. (M. Kornfeld)