Jonathan Edwards reminds us that our motivation to serve Christ should not be fear, but our desires, our affections, our loves. The following is from "Advice to Young Converts" (emphasis mine): 

When the exercise of grace is at a low ebb, and corruption prevails, and by that means fear prevails, don't desire to have fear cast out any other way than by the reviving and prevailing of love, for it is not agreeable to the method of God's wise dispensations that it should be cast out any other way. When love is asleep, the saints need fear to restrain them from sin, and therefore it is so ordered that at such times fear comes upon them, and that more or less as love sinks. But when love is in lively exercise, persons don't need fear. The prevailing of love in the heart naturally tends to cast out fear as darkness in a room vanishes away as you let more and more of the perfect beams of the sun into it: "There is no fear in love. But perfect love drives out fear, because fear has to do with punishment. The one who fears is not made perfect in love." (1 John 4:18)