Komentaryo sa Levitico 21:9: Rashi, Ibn Ezra, Rashbam & Rabbeinu Bahya

כי תחל לזנות means, if she profanes herself through unchastity, i. e. that a marriage-tie of some kind applied to her and she nevertheless prostituted herself either after betrothal (which constituted a kind of marriage-tie, since she would require a bill of divorce to enable her to marry someone else) or after marriage (having left her father's house for her husband’s). Our Rabbis are of different opinions regarding this (whether Scripture speaks here of an ארוסה or a נשואה), but all agree that Scripture is not speaking of a פנויה (a woman who is neither betrothed nor married) (cf. Sanhedrin 51b).

desecrates herself [Hebrew: teḥel] Many people say that this word comes from “beginning” [Hebrew: tḥilla]; but I believe it comes from “desecration” [Hebrew: ḥillul], except that here the word is in the hif‘il form, as in “he may not break his word” [Numbers 30:3]. Both opinions require the word to stem from an ‘ayin-‘ayin root, ḥ-l-l. The word, however, is irregular; and it seems likely that the reason for the irregularity, both in the infinitive haḥel [the heh is vocalized with a pattaḥ instead of a qammaṣ — Translator] as well as in this word teḥel (where the tav is vocalized with a ṣereh ), is to avoid confusion with “beginning”, the other meaning of the root. Compare, “that it should not be profaned” [Hebrew: heḥel] [Ezekiel 20:9].

ובת איש כהן, a girl who is already betrothed to be married. The details of this legislation are explained in Sanhedrin 50.

את אביה היא מחללת SHE PROFANETH HER FATHER — i. e. she profanes and makes light of his honor by her conduct (מחללת does not mean she causes him to become a חלל, one unfit for priestly service), in that people say about him, "Cursed be he who has engendered this woman; — cursed be he who has reared this woman” (Sanhedrin 52a).