To Learn or Not to Learn

Although this question has been worn thin by whining elementary school kids, I'm going to ask it. What is the reason behind learning? Why do I spend hours memorizing geometric theorems, dictionarying strange Spanish vocabulary, and researching the religious impact of the 30 Years War? I think to know the purpose of learning I must first know the purpose of life. Jesus's last commandment was to go our into all the earth and preach the gospel. In our society, it is virtually impossible to so that without an education. The biology that seems useless now will dill criteria for a good college that will prepare me for a good career that will empower me to share the gospel. But once many people have started a career they forget that the goal is not making money (which moth and rust destroys). The goal is saving souls. I would hate to invest 20 years of my life accumulating knowledge only to squander it on worldly pursuits.