Ketubot 25B

לאו כולהו סלוק.

not all of them ascended. Since the majority of the people did not come to the land, separating ḥalla was not restored to the status of an obligation by Torah law.

תא שמע: חזקה לכהונה ⁠— נשיאות כפים וחילוק גרנות ועדות. עדות חזקה היא? אלא לאו, הכי קאמר: נשיאות כפים כי עדות: מה עדות ליוחסין, אף נשיאות כפים ליוחסין! לא: עדות הבאה מכח חזקה ⁠— כחזקה.

The Talmud cites proof from another baraita to resolve the dilemma. Come and hear: The presumptive status for priesthood is established by Lifting of the Hands for the Priestly Benediction, and by distribution of teruma at the threshing floors, and by testimony. The Talmud asks: Does testimony merely establish presumptive status? Testimony provides absolute proof of his status, not merely a presumption. Rather is it not that this is what the tanna is saying: Lifting of the Hands is like testimony, just as testimony that one is a priest elevates him to the priesthood for lineage, so too Lifting of the Hands establishes presumptive status for lineage. The Talmud answers: No, when the tanna is referring to testimony, he is stating that the legal status of testimony that is based on presumptive status is like that of presumptive status itself.

כי ההוא דאתא לקמיה דרבי אמי, אמר ליה: מוחזקני בזה שהוא כהן. אמר ליה: מה ראית? אמר ליה: שקרא ראשון בבית הכנסת. בחזקת שהוא כהן, או בחזקת שהוא גדול? שקרא אחריו לוי. והעלהו רבי אמי לכהונה על פיו.

As in the incident involving a certain man who came before R' Ami and said to him: That man established presumptive status before me that he is a priest. R' Ami said to him: What did you see that led you to that conclusion? He said to R' Ami: I saw that he was called to the Torah and read first in the synagogue. R' Ami asked him: Did he read first based on the presumptive status that he is a priest, or was it based on the presumptive status that he is a great man? The custom was that a priest would be called to the Torah first, unless there was a prominent Torah scholar among the worshippers. He said to R' Ami: He read the Torah as a priest, as after him a Levite read the Torah. A Levite is called to the Torah second only when a priest is called first. And R' Ami elevated him to the priesthood, on the basis of his statement.