Remember in English, there is always an exception to every rule.
When a sentence starts with a he said/she said phrase and ends in quoted material, you should place a comma before the quote.
He said, “The proposal will be completed by Friday.”
However, if the introductory phrase forms a complete sentence, then place a colon before the quoted material.
He said something reassuring to the committee: “The proposal with be completed by Friday.”
In addition, if the quoted material contains more than one sentence, use a colon – not a comma.
He said: “The proposal will be completed by Friday. However, it will require the team to work overtime, and they will have to be paid for the extra hours.”
Note: Do not use a comma or a colon if the quoted material is preceded with the word that or if it flows into the sentence.
He said that “the proposal will be completed by Friday.”
In the minutes, it was noted that we “cannot complete the proposal before Friday.”
I have often said that “poor grammar is like bad breath. People will seldom tell you. But they sure notice it.”