Whosoever
* Function: Subject of the verb.
* Example: Whosoever believes in truth shall be saved.
Whomsoever
* Function: Object of the verb or preposition.
* Example: To whomsoever it may concern.
In essence:
* Whosoever is used when the person is performing the action.
* Whomsoever is used when the person is the recipient of the action or is being acted upon.
Modern Usage:
While grammatically correct, these words are rarely used in modern English, especially in casual conversation or writing. They sound very formal and somewhat outdated. It's generally more common to use "whoever" or "whomever" in their place.
Examples:
* Formal: Whosoever enters this room must sign in.
* Modern: Whoever enters this room must sign in.
* Formal: To whomsoever it may concern.
* Modern: To whomever it may concern.
If you're unsure about which word to use, it's usually safer to choose "whoever" or "whomever".