How it's written and how it's read teaches us something TB Pesakhim 26

 There are a couple of things that make the Torah so challenging for the Torah reader. First of all, there are no vowel notations. Only the consonants appear in the Torah scroll. Sometimes some letters serve as vowel markers. For example, a yod (י) can indicate the long e vowel. The second challenge is that a word may or may not have these vowel markers. If the word does, it is considered full or ketiv malai (כתיב מלא). If it doesn’t the word is considered lacking or ketiv hasair (כתיב חסר). In today’s daf TB Pesakhim 26 the rabbis learn an insight about driving benefit by the way the word is spelled in the Torah and how it is read.

“If a bird landed on the red heifer¹ it remains valid, since this is not considered to be like bearing a yoke. If a male animal mounted it to mate with it, it is unfit and may not be used for the ritual...The Gemara asks: What is the reason for the difference between the case where a bird lands on it and where a male animal attempts to mate with it?

“Rav Pappa said that the verse on the (egal arufa-gg) says: “And the elders of that city shall take a heifer of the herd, which has not been used for work, and which has not drawn in the yoke” (Deuteronomy 21:3). If it were written: “He worked [avad],” and we read: “He worked [avad],” this word choice would indicate that the heifer could still be used until he, the owner of the heifer himself, used it willingly for labor. If it were written: “It was worked [ubbad],” and we read: “It was worked [ubbad],” it would indicate that even if it performed labor on its own it is also prohibited to use it, since some form of labor had been done with it.

“Now that it is written: “He worked [avad-עָבַד],” but we read this word as: “It was worked [ubbad-עוּבַּד],” both meanings are intended: It is prohibited if it is worked in a similar manner to the way he works. In other words, just as the owner works the animal in a way that is beneficial to him, so too, the animal becomes prohibited only when it is worked in a way that causes him to derive benefit from this labor. Therefore, it still may be used if a bird lands on it, because the owner does not derive benefit from this in any way. However, if a male bull mates with this heifer it is rendered unfit, since the owner generally has an interest in this occurring.” (Sefaria.org translation)

1Neither the red heifer nor the egal arufa sacrifices to be acceptable were allowed to be put to work. The red heifer was used in the purification ritual. If a dead body was found between two towns and the murderer couldn't be found, the egal arufa was offered up as a sign that no one in the towns was responsible for this person death.