In 1951, C.S. Lewis exchanged several letters with Sheldon Vanauken, an American who had become a follower of Jesus at Oxford. Vanauken asked Lewis whether he should now take up theological studies and enter “Christian ministry.” Lewis suggested he shouldn’t, but his answer also offered a strong commentary on vocation. He noted everyone’s call, “whether they know it or not,” is to integrate, to “bring God into our work.”
On the whole, I’d advise you to get on with your tent-making. The performance of a duty will probably teach you quite as much about God as academic Theology wd. do. Mind, I’m not certain: but that is the view I incline to…
Look: the question is not whether we should bring God into our work or not. We certainly should and must: as MacDonald says, “All that is not God is death.” The question is whether we should simply (a.) Bring Him in in the dedication of our work to Him, in the integrity, diligence, and humility with which we do it or also (b.) Make His professed and explicit service our job. The A vocation rests on all men whether they know it or not; the B vocation only on those who are specially called to it. Each vocation has its peculiar dangers and peculiar rewards.
Sheldon Vanauken, A Severe Mercy, pp. 105-106.