Sanhedrin 29A

קרובים ונתרחקו הוו. אתו לקמיה לדינא. אמר להו: פסילנא לכו לדינא.

were relatives of his and became not related to him, as Mar Ukva’s wife, who was their sister, died. They came before him for judgment. Mar Ukva said to them: I am disqualified from adjudicating for you.

אמרו ליה: מאי דעתיך? כרבי יהודה? אנן מייתינן איגרתא ממערבא דאין הלכה כרבי יהודה.

They said to Mar Ukva: What is your opinion according to which you disqualify yourself? Do you rule in accordance with the opinion of R' Yehuda, that since you have children we are still relatives? We should bring a letter from the West, Eretz Yisrael, that the halakha is not in accordance with the opinion of R' Yehuda.

אמר להו: אטו בקבא דקירא אידבקנא בכו? דלא קאמינא פסילנא לכו לדינא, אלא משום דלא צייתיתו דינא.

Mar Ukva said to them: Is that to say that I am stuck to you with a kav of wax [kira]? I agree that we are not considered relatives; I am saying that I am disqualified from adjudicating for you only because you will not obey the verdict, and I do not wish to participate in such judgment.

אוהב זה שושבינו וכו׳.

§ The Mishnah teaches that according to R' Yehuda, one who loves or one who hates one of the litigants is disqualified from bearing witness. One who loves one of the litigants; this is referring to his groomsman.

וכמה? אמר רבי אבא אמר רבי ירמיה אמר רב: כל שבעת ימי המשתה. ורבנן משמיה דרבא אמרי: אפילו מיום ראשון ואילך.

The Talmud asks: And for how long is the groomsman disqualified? R' Abba says that R' Yirmeya says that Rav says: Throughout all of the 7 days of feasting. And the Rabbis say in the name of Rava: Even from the 1st day after the wedding and onward he is no longer disqualified; he is disqualified only on the wedding day itself.