If You are Looking for Referrals
It only makes sense that when someone receives something awesome and wonderful, they will want to brag about it and share it. To get a referral it only makes sense that the person who is giving a referral can only do so if they have personally experienced or seen first hand the awesomeness and amazing product or service. To risk one's reputation and give attention to another by giving a referral should be considered the most generous gifts one can give another.
If all this is true, then which is more important if you are looking for a referral?
If you talk, sell, promise, yakityyakity; you are the same as everyone.
When you do, build, produce, commit with action, sacrifice... then others experience the reality of what you provide.
You can talk about what you might do in the future
You can do something amazing and awesome for others which gives someone something to talk about (and refer).