Why should you open your speech with a quotation?

1. It will build your credibility. If you choose a striking quotation, or one from someone the audience knows well. If you quote someone the audience knows you call up the reputation and memory of that famous person, and that gives an additional power to the words.
2. It will support your persuasion. Before you choose the quotation, know what you want to say and achieve with the speech. What is the central message? What emotions do you want to call up at the beginning of your speech? You can use the quotation to set the scene for the speech, or even to be a summary of your message, and something you can call back to during your speech for added emphasis.
3. It will allow you to be present with your audience. While it works best if it relates directly to your content. There may be occasions, though, where it can relate to your audience, or the venue or occasion. This personalises your speech and allows you to connect with your audience. It should, however, allow for a minimal amount of time to link, then to your message
4. It will reinforce that presence, and allow connection with your audience, allowing them to buy in to your speech. Oftentimes there is huge power in pausing after the quote to let it sink in, to let your audience nod in agreement or wonder just what you are going to achieve with it. It may be something funny, so wait for the amusement to register.
Make sure to emphasise the emotion that you want to project with the quote. Use gesture and facial expression that will heighten the response you want. Smile when the audience has registered amusement for example. Give a heightened shrug if the quotation comes in the form of a question
Obviously there will be other times when you need to go straight to the next sentence. This is especially true if it is a well known quote, or if you are going to disagree with it. … and that
5. Supports the rhythm of your speech.
.
If you choose quotations that contribute to the message and emotional tone of your speech and if you support that contribution with your delivery, they can be a powerful opening to your speech.