Jerusalem Talmud Yevamot 5:3

משנה: נָתַן גֵּט וְעָשָׂה מַאֲמָר צְרִיכָה גֵט וַחֲלִיצָה. נָתַן גֵּט וּבָעַל צְרִיכָה גֵט וַחֲלִיצָה. נָתַן גֵּט וְחָלַץ אֵין אַחַר חֲלִיצָה כְּלוּם. MISHNAH: If he delivered a bill of divorce and then “bespoke”, she needs a bill of divorce and ḥalîṣah. If he delivered a bill of divorce and then cohabited, she needs a bill of divorce and ḥalîṣah. If he delivered a bill of divorce and then performed ḥalîṣah, after ḥalîṣah nothing more is needed.

הלכה: נָתַן גֵּט וְעָשָׂה מַאֲמָר כול׳. גֵּט לְמַאֲמָרוֹ וַחֲלִיצָה לְזִיקָתוֹ. HALAKHAH: “If he delivered a bill of divorce and then “bespoke”, etc. A bill of divorce for his “bespeaking” and ḥalîṣah for her candidacy⁴⁷The bill of divorce is only enough to forbid the widow to himself and all brothers but it does not fulfill the requirements of Deut. 25:5–9. Since “bespeaking” is rabbinic, the bill of divorce will be rabbinic (Babli 50b)..

הָדָא אָֽמְרָה. בִּיאָה פְסוּלָה אֵינָהּ פּוֹטֶרֶת. אִיתָא חֲמִי. חֲלִיצָה פְסוּלָה פוֹטֶרֶת וּבִיאָה פְסוּלָה אֵינָהּ פּוֹטֶרֶת. חֲלִיצָה עַל יְדֵי שֶׁעִיקָּרָהּ פְּסוּלָה פּוֹטֶרֶת. בִּיאָה עַל יְדֵי שֶׁאֵין עִיקָּרָהּ פְּסוּלָה אֵינָהּ פּוֹטֶרֶת. וְלֹא תִפְטוֹר בָּהּ לַקּוּל וְתִפְטוֹר בָּהּ לַחוֹמֶר. וְלֵיי דֶא מִילָּה. שֶׁאִם בָּא אֶחָד וְקִידֵּשׁ אֶת הַצָּרָה תָּֽפְשׂוּ בָהּ קִידּוּשִׁין. אָמַר רִבִּי יוּדָן. קִייַמְתִּיהָ. כָּל־יְבָמָה שֶׁאֵין כּוּלָּהּ לַחוּץ לְעוֹלָם הִיא בִפְנִים עַד שֶׁתֵּצֵא לַחוּץ. That means⁴⁸This refers to the statement that intercourse after divorce is invalid; it is incestuous. The sister-in-law may not become his wife. Therefore, a co-wife is not freed to marry outside the family. that invalid intercourse does not free. Come and see, invalid ḥalîṣah⁴⁹An invalid ḥalîṣah is one where levirate is impossible, as in the last case of the Mishnah. As the Mishnah notes, a ḥalîṣah is always final. frees but invalid intercourse does not free! Since the purpose of ḥalîṣah is invalidation, it frees. Intercourse, whose purpose is not invalidation, does not free. It should not free for leniency but might free for restriction. In which respect? If somebody came and gave qiddushin to the co-wife, these should lay hold on her. Rebbi Yudan said, I explained it. Any sister-in-law who is not totally outside remains inside until she leaves for the outside⁵⁰Since a widow under the obligation of levirate in unable to contract another marriage before the candidacy for levirate is lifted for her, no widow can remarry outside the family as long as not all required ceremonies have been performed..