Bava Metzia 55A

באמצע הקדש, ליתה? אמר ליה: לפי שאינה בסוף הקדש.

but it is not subject to an intermediate stage of consecration resulting from redemption? Ravina said to him: It is due to the fact that it is not subject to ultimate consecration. A non-kosher animal does not ultimately remain consecrated, as it is used neither as an offering nor in the upkeep of the Temple. Instead, it is redeemed and its value is consecrated.

אמר ליה רב אחא: מדיפתי לרבינא, באמצע הקדש מיהא איתה, ולוסיף נמי חומש! אמר ליה: הרי הוא כסוף הקדש, מה סוף הקדש אינו מוסיף חומש ⁠– אף אמצע הקדש אינו מוסיף חומש.

Rav Aḥa of Difti said to Ravina: It is subject, at least, to an intermediate stage of consecration; and in that case, let one add 1/5th as well. Ravina said to him: Its legal status is like that of ultimate consecration: Just as one does not add 1/5th with regard to a non-kosher animal in ultimate consecration, as that category does not exist in a non-kosher animal, so too, one does not add 1/5th in a case of intermediate consecration.

אמר ליה רב זוטרא בריה דרב מרי לרבינא: מאי חזית דמדמית ליה לסוף הקדש? נדמייה לתחילת הקדש! אמר ליה: מסתברא לסוף הקדש הוה ליה לדמויי, שכן נתפס מנתפס. אדרבה: לתחילת הקדש הוה ליה לדמויי, שכן דבר שיש אחריו קדושה מדבר שיש אחריו קדושה!

Rav Zutra, son of Rav Mari, said to Ravina: What did you see that led you to liken the intermediate stage of consecration to ultimate consecration? Let us liken it to initial consecration. Ravina said to him: It stands to reason that he should liken it to ultimate consecration, as he thereby derives the halakha of an item consecrated by association with the sanctity of an item consecrated by association. The Talmud asks: On the contrary, he should have likened it to initial consecration, as he thereby derives the halakha of an item after which there is another stage of sanctity, the intermediate stage of consecration, from an item after which there is another stage of sanctity.