Paul J. Tillich, who until his death in the mid-1960s was one of America’s best-known theologians. He established his career in his native Germany before coming to the US during the rise of Hitler and later becoming an American citizen. He was a constant student of the Scripture; his students claimed that he could quote the entire Greek NT from memory. On his deathbed he asked his wife to read to him again from his beloved Greek New Testament. Yet Tillich was a regular user of pornography and repeatedly was unfaithful to his wife. Furthermore, “The System,” as he called his theological beliefs, rejected the importance of the literal truth of Scripture or even the literal existence of Jesus Christ. He played a major role in applying existentialist philosophy to Scripture and in so doing helped place a wedge between an entire generation of theological students and the God they studied.
The Holy Spirit brings about salvation in our hearts. No amount of study will enable a man to know God apart from the Holy Spirit.
From my study in the BJU British Literature Curriculum