I am reading The Blue Book of Grammar and Punctuation, and it advocates not using quotation marks after a colon.
"
Rule 5. Use the colon to introduce a direct quotation that is more than
three lines in length. In this situation, leave a blank line above and below
the quoted material. Single space the long quotation. Some style manuals
say to indent one-half inch on both the left and right margins; others say
to indent only on the left margin. Quotation marks are not used.
Example:The author of Touched, Jane Straus, wrote in the first chapter:Georgia went back to her bed and stared at the intricatepatterns of burned moth wings in the translucent glass ofthe overhead light. Her father was in ‘‘hyper mode’’ againwhere nothing could calm him down.He’d been talking nonstop for a week about remodelingprojects, following her around the house as she tried toescape his chatter. He was just about to crash, she knew."Conversely, I did some search and came across this blog which advocates using them.
http://www.grammar-monster.com/lessons/quotation_%28speech%29_marks_colon_or_comma.htmSeriously, this is getting weird. I am starting to think that even grammar savvy people cannot agree anymore.