The Importance of Fearfulness

If Christians are certain to be forgiven, then is there any drive for one to be a good person? Do whatever we want and we will still be forgiven. I would say that fearfulness, a fear of missing out on eternal life because I better live a good enough life. It's true that fearfulness does produce a lot of good works. But it's not clean energy. You can do all those good deeds basically by offering certainty.