There are different ways to introduce a quote in a grammatically correct way. One way is to use an introductory sentence followed by a colon. Another way is to integrate the quote into your own sentence. You can also use an introductory signal phrase, such as the author's name or credentials, the title of the source, and/or helpful background information. Descriptive verbs like "states," "remarks," "notes," "comments," or "maintains" can also be used to introduce a quote in a brief and concise way.