In the seventh chapter of Matthew, Jesus made the statement, "You will know them by their fruits." We often think this is how we'll know those who are considered to be sincere believers, but the context is being aware of false prophets. They are the ones focusing on establishing themselves with good works, performance and attempting to produce their own fruit. You will know them by their fruits. This is in contrast to the fruit of the Spirit, which is not produced by our good works but rather by God who bears His fruit through us.