In his 1867 Inaugural Address at Columbia Theological Seminary, William Swan Plumer explained what ought to be the right "temper" of the student of God's word. You can find his address along with others works we've posted by him, but here's a sneak peek to the answers he gives: the theologian should possess modesty, impartiality, independence of thought and freedom of inquiry, profound reverence for what he studies, a love of truth, patience, a spirit of diligence, a genuine lively faith, just moderation, the spirit of prayer, a commitment to practice what he learns, and a gospel centered, evangelical spirit. The address is only 16 small pages, so make sure to read how Plumer unpacks each of these points.
(This is actually an abridged version of his address, published for the popular press as a booklet. You can find the entire address in the Southern Presbyterian Review , 19.1 (January 1868), which we have not posted to our site yet!)