Gittin 60A

מי קוראין? לא הוה בידיה. אתא ושייליה לרבי יצחק נפחא, אמר ליה: אחריהן קוראין תלמידי חכמים הממונין פרנסים על הצבור, ואחריהן תלמידי חכמים הראויין למנותם פרנסים על הציבור, ואחריהן בני תלמידי חכמים שאבותיהן ממונים פרנסים על הצבור, ואחריהן ראשי כנסיות וכל אדם.

who reads from the Torah? An answer was not readily available to him. He came and asked R' Yitzḥak Nappaḥa, who said to him: After them read the Torah scholars who are appointed as leaders [parnasim] of the community. And after them read Torah scholars who are fit to be appointed as leaders of the community, even if in practice they received no such appointment. The rabbis said that a Torah scholar who knows how to answer any question asked of him is fit to be appointed as leader of the community. And after them read the sons of Torah scholars whose fathers were appointed as leaders of the community. And after them read the heads of synagogues, and after them any person.

שלחו ליה בני גליל לרבי חלבו: מהו לקרות בחומשים בבית הכנסת בציבור? לא הוה בידיה. אתא שייליה לרבי יצחק נפחא, לא הוה בידיה. אתא שאיל בי מדרשא, ופשטוה מהא דאמר רבי שמואל בר נחמני אמר רבי יוחנן: ספר תורה שחסר יריעה אחת ⁠– אין קורין בו.

The people of the Galilee sent a question to R' Ḥelbo: What is the halakha with regard to reading from ḥumashim, i.e., scrolls containing only one of the 5 books of the Torah, in the synagogue in public? Is this permitted, or is it necessary to read from a complete Torah scroll? An answer was not readily available to him. He came and asked R' Yitzḥak Nappaḥa, but an answer was not readily available to him either. R' Yitzḥak Nappaḥa came and asked this question in the study hall, and they resolved the difficulty from that which R' Shmuel bar Naḥmani says that R' Yoḥanan says: With regard to a Torah scroll that is missing even one sheet of parchment, one may not read from it in public. This indicates that an incomplete Torah scroll may not be used for a public Torah reading.