Keep your eyes open, hold tight to your convictions, give it all you've got, be resolute, and love without stopping. 1 Corinthians 16:12-15 (MSG)
"Knowing what to do is worthless if you don't have the conviction to motivate you to actually do it! "
A person without conviction is at the mercy of circumstances. If you don't determine what's important and how you'll live, other people will determine it for you.
A person without conviction is a weak, jellyfish type of individual who mindlessly follows the crowd. I believe Paul was talking about conviction when he said in Romans 12:2, "Don't let the world squeeze you into its own mold, but let God remold your mind from within ...." (Phillips)
Conviction helps us be diligent in continuing to grow spiritually. Growth requires time and effort. Without convictions about growth, people become discouraged and give up. No one stays with a difficult task unless he is convinced that there is a good reason for doing it. A church can teach people how to pray, how to study the Bible, and how to witness, but without imparting the corresponding convictions, people will not stick with it.
Knowing what to do (knowledge), why to do it (perspective) and how to do it (skill) is all worthless if you don't have the conviction to motivate you to actually do it!
The people who have made the greatest impact on this world, for good or evil, were the people with the strongest, deepest convictions. They weren't necessarily the smartest, wealthiest, or best educated people but their convictions moved them to move the world.