[Our Mishnah taught] Giso - some teach that he has sons and Chasanim (e.g. David has sons and Chasanim who cannot testify for Levi, without married David's wife's sister), and some teach that he does not have [Pasul] sons and Chasanim;

The one who says that [David] has sons and Chasanim - it is from her (his wife), and the one who says he does not have sons and Chasanim, i.e. from another wife (they can testify for Levi).

Rav went to bring hides for R. Chiyah Rabah [to write Chumashim on them - KORBAN HA'EDAH]. He went to one place and found R. Yochanan sitting and asking "our Mishnah taught his stepson alone - what is the law of his stepson's wife, or his stepdaughter's husband? Do we say that a woman is like her husband, and a husband is like his wife?

They concluded that his stepson's wife is like a stepson, and a husband is like his wife. (The Mishnah said "alone" to exclude his sons and Chasanim.)

Question (Rav Chisda): Is the third generation permitted with the wife of the first generation? May Moshe testify for the wife of Pinchas (the grandson of his brother)?

Answer #1 (Reish Lakish): We accept the second and third generations [to testify about the first] in pressed circumstances.

Answer #2 (R. Yochanan): [We accept them] freely.

(The Mishnah says that one who was a relative and was distanced is Kosher; R. Yehudah says, even if his daughter died and he has children from her, he is disqualified.) This is like Rav Huna's Gis (who became distanced). He had a Din with someone. He said "whatever Rav Huna will say, I accept on myself";

Rav Huna heard, and said like this (that he is Kosher now). I know that just like they argue above, they argue below. (Since R. Yehudah said "even..." this shows that the first Tana argues is Machshir also a son-in-law who was distanced. Surely, he is Machshir two Gisim when one of their wives died.)

(Rav Yehudah citing Rav): The Halachah follows R. Yehudah (he is disqualified).

(Mishnah): A close friend or enemy cannot testify. A close friend refers to a Shushbin (one who brought gifts to a Chasan). An enemy is one who did not speak to him for three days due to hatred. (R. Yehudah, who taught the end of the previous Mishnah, taught also this.)

Chachamim: Yisraelim are not suspected of this [to testify falsely due to love or hatred].

(Gemara - R. Tavlai citing R. Avina citing Rav): [A Shushbin is Pasul] during the the seven days of Mishteh (nuptial feasts).