The Torah prescribes a vivid ritual for a Hebrew servant who refuses to go free after six years of service: "Then his master shall bore his ear" with an awl against a doorpost (Exodus 21:6). The Mekhilta asks a pointed question: why does the Torah need to state this at all? In Jewish law, a well-established principle says that a person's messenger is equivalent to the person himself. Whatever you can do, your appointed agent can do on your behalf.
But the ear-boring ceremony is different. The Torah says "his master shall bore his ear," and the Mekhilta reads the emphasis carefully: his master, and only his master. No delegate. No proxy. No agent. The master must hold the awl and push it through the cartilage himself.
This exception to the normal rules of agency is loaded with meaning. The ear-boring is not a routine legal transaction. It is a profound and troubling moment in which one human being permanently marks another. The servant is choosing to remain in bondage, and the master is accepting that choice by physically piercing the servant's body. The Torah insists that this act cannot be delegated because it must be felt. The master must look into the face of the person he is binding. He must feel the resistance of flesh against metal. Sending a messenger would sanitize the act, would allow the master to avoid confronting what permanent servitude truly means. The Mekhilta refuses to let him look away.