Check out this quote from G. Campbell Morgan,
No psychology will ever effect conversion. Regeneration must affect psychology.
The Gospel According to John, 1908, p. 58; emphases mine
The context of these two sentences are Morgan’s description of Jesus words to Nicodemus in John 3:3. He is not talking about psychology in the more modern sense we might intend today. What he is saying is that one must be “born again” in order to see the kingdom of God. One cannot think, feel, or perceive the real truth about God–no matter how psychologically mature and aware–without the work of the Spirit.
Notice his use of the words effect and affect. I didn’t have great English grammar education so I will assume some of you also might miss the meaning. Here’s my rewrite of his sentences
Psychological maturity cannot bring you to full awareness of God and creation but conversion will definitely impact your psychological well-being, you soul.
If you are interested in reading this book, you can find the full text on-line here. His comments on the interaction between Nicodemus and Jesus are very enlightening and provide a different perspective than is often given. He gives Nicodemus a lot more credit than do many preachers.