Devarim - Deuteronomy - Chapter 7, verses 1-4
א. כִּי יְבִיאֲךָ יְ־הֹוָ־ה אֱלֹהֶיךָ
אֶל הָאָרֶץ אֲשֶׁר אַתָּה בָא שָׁמָּה
לְרִשְׁתָּהּ וְנָשַׁל גּוֹיִם רַבִּים
מִפָּנֶיךָ הַחִתִּי וְהַגִּרְגָּשִׁי
וְהַפְּרִזִּי וְהַחִוִּי וְהַיְבוּסִי
שִׁבְעָה גוֹיִם רַבִּים וַעֲצוּמִים
ב. וּנְתָנָם יְ־הֹוָ־ה אֱלֹהֶיךָ
לְפָנֶיךָ וְהִכִּיתָם הַחֲרֵם
תַּחֲרִים אֹתָם לֹא תִכְרֹת לָהֶם
בְּרִית וְלֹא תְחָנֵּם:
ג. וְלֹא תִתְחַתֵּן בָּם בִּתְּךָ לֹא
תִתֵּן לִבְנוֹ וּבִתּוֹ לֹא תִקַּח
ד. כִּי יָסִיר אֶת בִּנְךָ מֵאַחֲרַי
וְעָבְדוּ אֱ־לֹהִים אֲחֵרִים וְחָרָה
אַף יְ־הֹוָ־ה בָּכֶם וְהִשְׁמִידְךָ
- When the Lord, your God, brings you into the land to to which you are
coming to possess it, He will cast
away many nations from before you: the
Hittites, the Girgashites, the
Amorites, the Canaanites, the
Perizzites, the Hivvites, and the
Jebusites, seven nations more numerous
and powerful that you.
- And the Lord, your God, will deliver them to you, and you shall
smite them. You shall utterly destroy
them; neither shall you make a
covenant with them, nor be gracious to
- You shall not intermarry with them; you shall not give your daughter to
his son, and you shall not take his
daughter for your son.
- For he will turn away your son from following Me, and they will worship
the gods of others, and the wrath of
the Lord will be kindled against you,
and He will quickly destroy you.
Rashi on verse 4 says Based on the Gemara in Kiddushin 68B (Original, English):
Verse 4: For he will turn your son
away from me.
If the son of the gentile will marry your daughter, he will turn away
your son (grandson) whom your daughter
will bear for him, from following
after Me. From this we learn that your
daughter's son, who is born of a
gentile, is considered your son; but
your son's son, born of a gentile
woman, is not considered your son, but
rather her son; for it is not said
[regarding the prohibition:] "Do not
take his daughter for you son,"
because she will turn [your (grand)son
away from Me], but only that he (the
gentile) will turn your son, etc.
You can see more of the same discussion here.
As an aside (since it was asked above):
The Lubavitcher Rebbe once wrote in a letter (I don't have the source right now), that it makes sense logically that Jewishness goes after the mother and lineage (e.g Cohen or Levi) goes after the father:
- Since the essential existence of the baby is developed entirely by the mother in her womb, it makes sense that the essential nature of the baby (i.e. jewish or not) is determined by the nature of the mother.
- On the other hand, being a Cohen or Levi involves practical action (namely, serving in the Holy Temple), and it is the father who is obligated to teach the son. Also, the father is the one who is obligated and actually performs the service, not the mother. So the child learns from the father how to be a Cohen or Levi. Therefore it makes sense that lineage goes after the father.