Jerusalem Talmud Sanhedrin 3:7

משנה: הָאוֹהֵב וְהַשּׂוֹנֵא. אוֹהֵב זֶה שׁוּשְׁבִין. שׂוֹנֵא כֹּל שֶׁלֹּא דִבֶּר עִמּוֹ שְׁלשָׁה יָמִים בְּאֵיבָה. אָמְרוּ לֹו לֹא נֶחְשְׁדוּ יִשְׂרָאֵל עַל כָּךְ׃ MISHNAH: ¹¹⁹The Mishnah is a continuation of R. Jehudah’s statement. The lover and the hater¹²⁰Are disqualified as witnesses.. The lover, that is the best man. The hater, anyone who did not talk to him for three days because of ill-will. They told him, Israel are not suspected of this¹²¹To testify falsely because of this. But a judge emotionally involved with one of the parties is disqualified (Babli 29a)..

הלכה: הָאוֹהֵב וְהַשּׂוֹנֵא כול׳. רִבִּי טֶבְלַיי רִבִּי אַבִּינָּא בְשֵׁם רַב. בְּשִׁבְעַת יְמֵי הַמִּשְׁתֶּה שָׁנוּ. HALAKHAH: “The lover and the hater,” etc. Rebbi Tevelai, Rebbi Abinna in the name of Rav: They stated this for the seven days of wedding festivities¹²²The best men are disqualified only during the festivities. Rav’s opinion is quoted in the Babli, 29a, where a later authority restricts R. Jehudah’s rule to the wedding day only..