Halakhah for Ketubot 10:21

And the root of this commandment and all of its content is in the commandment that is before it. And since this verse has come to our hand, we will write the midrash about it; that they, of blessed memory, affixed to it in the gemara, when they said (Ketuvot 5b), "Why are the fingers of a person made like spikes" - which is to say, tapered? "So that if a person hears a thing that is not proper, he should put his finger into his ear (ozen), as it is stated, 'With your aazen you shall have a spike' - do not read, 'your aazen,' but rather your ozen.'"