As a young man of 22, Charles Hodge, the great Princeton theologian, was extremely self-reflective about his spiritual affections. He intently searched his emotions and thoughts to gauge his spiritual state. Then, he seems at one point (recorded in his journal) to realize that such introspection was not profitable. As he biography Hoffecker explains:

That is, he found the more a person examined his subjective spiritual state, the less apt he was to experience what he was looking for because he sought something that was not under his control. When focusing so intently on experience, the cognitive act itself preceded a person’s experiencing the alternative subjective activity being sought. Genuine spiritual “experience” wold come not as the result of efforts to achieve it but as something given by God. Hodge hereby recognized an irony in spiritual experience. The religion affections were not subject to human manipulation; rather than being under human control, they arise as a gift. Thus, when Hodge was least apt to think positively about his experience because of spiritual depression, taking his thoughts off looking for the beginning of spiritual impressions actually freed his mind so that the affections stirred by God could arise. Perhaps Hodge came to realize that description of pious experience such as those he narrates in his diary were a disguised form of what he would condemn in other contexts as ‘works righteousness.’

W Andrew Hoffecker, Charles Hodge: The Pride of Princeton, American Reformed Biographies (Phillipsburg, N.J.: P & R Pub., 2011), 61.

This is a detailed, well-researched and very readable biography of Charles Hodge. Recommended.