Comentario sobre Levítico 13:5

בעניו means in its original colour and size.

AND THE PRIEST SHALL LOOK AT HIM ON THE SEVENTH DAY, AND BEHOLD, IF THE PLAGUE STAY ‘B’EINAV.’ “This means in its original color and size.”⁸⁵The literal meaning of b’einav is “in his eyes,” i.e., the eyes of the priest examining the plague. Ramban will further on stress this literal meaning of the word. This is Rashi’s language. Similarly, ‘v’eino’ (and the appearance thereof) was as the appearance of bdellium;⁸⁶Numbers 11:7. and so also, ‘k’ein’ (like the color of) the crystal ice.⁸⁷Ezekiel 1:22. These two verses bear out Rashi’s interpretation of einav as meaning “its appearance,” thus making the sense of the verse to be: and, behold, if the plague stay ‘in its appearance.’
But in the Torath Kohanim we have been taught as follows:⁸⁸Further, Verse 37. Thus if after having shut the person up in a house for seven days, the priest is in doubt whether the plague has spread [in which case he would pronounce it at once as a genuine case of leprosy], but his son or pupil who saw it at the beginning says definitely that the affliction did not spread, the priest may follow their opinion and may shut him up for another seven days. See my Hebrew commentary p. 70, for further discussion of this point. “[From the expression here] I know only that the plague so appeared [i.e., in its original size] in his own [i.e., the priest’s] eyes. Whence do I know that the same law applies if it so appeared in the eyes of his pupil? Scripture therefore says [in Verse 27]. But if the scall stay ‘b’einav.’” Now if so, the meaning of the verse here would be: “and if the plague is at a stay in the sight of the aforementioned priest,” namely that it has remained as it was, neither having changed its place nor having spread in the skin, wheresoever the priest looks [then he shall shut him up for another seven days]. The usage [of the term a’yin (eye)] is often found in the words of the Sages.⁸⁹The term chachamim (Sages) is evidently used by Ramban here not in the strict sense of the term, as referring to the Sages of the Talmud, as I have not found this expression in Talmudic literature. It must then be a reference to the later scholars in whose writings this expression abounds. Thus: “So it appears in my eyes.” So also you find [in Scripture]: O man of G-d, I pray thee, let my life be precious ‘b’einecha’ (in thy sight],⁹⁰II Kings 1:14. meaning, in your opinion and thought. Thus the verse here alludes to the principle that the priest in examining whether the plague has extended in the skin need only judge it as he sees it, but it is not necessary that [he base his decision] upon measuring the plague.

וראהו הכהן, it is a decree by the Torah that only a priest is qualified to determine what is ritually pure and what is ritually impure in all matters pertaining to these skin afflictions. The prophet Maleachi 2,7 echoes this concept when he says that כי שפתי כהן ישמרו דת, “that the lips (pronouncements) of the priest will preserve the Jewish religion.” The priest is also required to counsel the afflicted person to examine his lifestyle so that he himself will become the key to his rehabilitation. At the same time the Priest will add his own prayer when asking G’d to heal the afflicted. Apart from his prayer his expertise will tell him when the stage has been reached when the affliction has waned so that the count toward rehabilitation and the presentation of offerings can begin.