Fr Matthias Scheebenon the Holy Spirit's Role in the Theologian

Although the understanding and scientific development of the content of the faith in itself can and should be achieved through the natural power and activity of reason, but in service to and with the aid of faith, nevertheless for the successful and appropriate operation of reason along this line and for the attainment of a living and fruitful knowledge, some supernatural influence and support of the Holy Ghost is in part morally necessary and in part extremely useful and advantageous on account of the supernatural grandeur of the objects.  And in fact it is also all the more connected with theological knowledge, since this stands in teh most intimate relation on the one hand to supernatural faith, in which it is itself rooted, and on the other hand to the supernatural life that ought to proceed from faith.  By dint of this twofold relation and the influence of the Holy Ghost corresponding to it, theology attains the character of a sacred science, which distinguishes it from all other sciences as essentially profane ones and therefore also places it in an entirely special way under the influence and the authority of the visible organ of the Holy Ghost, the Church.  These statements are explained and substantiated in the following theses.

Above all some supernatural assistance of the Holy Ghost that illumines reason is morally necessary for theological knowledge for the same reasons on account of which it is necessary also for faith, disregarding the substantially supernatural character of the latter, namely because the nature of the subject on the one hand and of the object on the other hand entails great difficulties  for the correct and full understanding of the content of faith.  As for the subject, these difficulties lie in the dependence of all intellectual knowledge generally on the senses, and also in the confusing influences of prejudices, passions, ill will, and evil spirits.  As for the object they lie in the superiority of the content of faith over the entire circle of natural ideas.  In the first respect therefore the illumination of the Holy Ghost must first exert a negative, purifying influence on the eye of reason, but in the second respect that is positive, enlightening, in order to conform and relate the natural ideas to the supernatural objects.

Fr Matthias Scheeben,
Handbook of Catholic Dogmatics, 1.2