Sanhedrin 30B

ודכולי עלמא כרבנן דפליגי עליה דרבי יהושע בן קרחה, והכא באקושי הגדה לראיה קא מיפלגי. מר סבר: מקשינן הגדה לראיה, ומר סבר: לא מקשינן.

and everyone, both the first tanna and R' Natan, holds in accordance with the opinion of the Rabbis who disagree with R' Yehoshua ben Korḥa, and derive from this verse that it is necessary that the witnesses see the incident together, i.e., they were both present and observed the incident at the same time. And here, with regard to whether or not the witnesses must testify in court together, they disagree with regard to whether or not the statement of the witnesses, i.e., their testimony in court, is compared to their observation of the incident. One Sage, the first tanna, holds that we compare their statement to their observation. Therefore, just as they must see the incident together, so too, they must testify together in court. And one Sage, R' Natan, holds that we do not compare their statement to their observation.

רבי שמעון בן אליקים הוה משתקיד עליה דרבי יוסי ברבי חנינא למסמכיה, ולא קא מיסתייע מילתא. יומא חד הוה יתיב קמיה דרבי יוחנן,

The Talmud relates: R' Shimon ben Elyakim was striving to ordain R' Yosei, son of R' Ḥanina, and was not successful in his attempts. One day, R' Shimon ben Elyakim was sitting before R' Yoḥanan among R' Yoḥanan’s other students.

אמר להו: מי איכא דידע הלכה כרבי יהושע בן קרחה, או לא? אמר ליה רבי שמעון בן אליקים: דין ידע. אמר ליה: לימא איזו. אמר ליה: ליסמכיה מר ברישא. סמכיה.

R' Yoḥanan said to his students: Is there anyone who knows whether the halakha is in accordance with the opinion of R' Yehoshua ben Korḥa, or not? R' Shimon ben Elyakim said to him: This one, R' Yosei, son of R' Ḥanina, knows. R' Yoḥanan said to him: If so, let him say. R' Shimon ben Elyakim said to him: Let the Master ordain him first; since we are all in need of his wisdom, he is fit for ordination. R' Yoḥanan then ordained R' Yosei, son of R' Ḥanina.