Christians have disagreed wildly over the years about how to interpret the Holy Spirit as part of the Holy
Trinity. During the early years of Christianity, rival
Christian sects use to literally massacre each other to death while arguing whether the Holy spirit is "homoiousion" (of the similar substance) or "homousion" (of the same substance) as God. Of course it was all politics (a great book on that era is
Gore Vidal's
Julian). Even today, various
Christian groups (Catholic, Orthodox, Protestant, etc) are completely at odds about what exactly the Holy Spirit stands for.