just use:
raidsay Rezzing SELECTED
You don't really need the double quotes unless you are using special characters. Putting quotes around the "SELECTED" will cause it to read like normal text.
Here's an example of a more advanced setup
raidsay "Here's a rezz for " SELECTED ". Get up ya lazy bum!"
Output: Here's a rezz for Drumstix. Get up ya lazy bum!
Note how the quotes are only surrounding the plain text, and not the variable for SELECTED