This analogy has two main applications:
1. Christ made it clear that we, as branches, must abide in the Vine--must stay close and attached to Jesus Christ (John 15:1-8).
2. Viewing doctrines (biblical teachings) as branches, we should focus most of our study on the major branches. When we start focusing on smaller and smaller branches (even twigs), we get into trouble. We get sidetracked from our mission and become unbalanced. God doesn't want us to major in the minors.