This is the 2079th most frequent Korean word.
씨에게
"씨에게" means "to Mr./Ms. [name]" or "to [person]" in a formal and respectful way.
In this sentence, "씨에게" is used to indicate the recipient of the action, specifically someone addressed politely with "씨" followed by "에게" which means "to."
철수 씨에게 책을 주었습니다.
I gave the book to Cheol-soo.
Here, "씨에게서" is used to indicate the origin of the action, denoting the source of the message coming "from" a polite address of "씨."
유진 씨에게서 메시지를 받았습니다.
I received a message from Yoo-jin.
In this context, "씨에게" functions to show the target of the gratitude, addressing the recipient formally and politely.