Why study so hard?

As you know, it is exam season - O and A level - in my family now. A few days ago, one of them asked me this question, "dad, what actually is a good motivation for studying so hard?" I was stunned for a while. In that few seconds before I provided an answer, a number of thoughts ran through my mind (and still running ...). I couldnt make myself say, "to do well in exams so as to get a well-paying job next time." Although it is true that the correlation between good results and well-paying jobs is high, I am hesitant to give the impression that the greatest motivation for her to study is to land her with a well-paying job in future. It has too strong a pragmatic bend to it. And, if the ultimate purpose for a 'good job' is to earn lots of money, then there is a further materialistic ring to it as well. I am aware that other parents would have no qualms providing well-paying jobs as a motivation for their children to study hard, and I can understand why. But, as a Christian parent, I believe there should be more to it. It has to do with the goal of study - knowledge. [there is of course a difference between "study hard" and "study hard for exams". The latter is very narrow in scope; the former has to do with a disposition towards the acquisition of knowledge]. I would like my children to see knowledge as derived ultimately from God - it is worth acquiring in its own right insofar as it helps us to know God and His creation order better, not just because of the extrinsic rewards as a result of the knowledge acquired. In this sense, studying hard to acquire knowledge is one way to realize our potential as His creatures - to know Him and to understand the world that He has called us to subdue. Well, for obvious reasons, I didn't provide such a long answer to my daughter. I just said to her, "well, this is your current station of life - as a student - that God has called you into right now. For that, you need to be faithful to your calling - by studying hard."