You too, if you would make prudent progress in your studies of the mysteries of the faith, would do well to remember the Wise Man’s advice: “Do not try to understand things that are too difficult for you, or try to discover what is beyond your powers.” These are occasions when you must walk by the Spirit and not according to your personal opinions, for the Spirit teaches not by sharpening curiosity but by inspiring charity. And hence the bride, when seeking him whom her heart loves, quite properly does not put her trust in mere human prudence, nor yield to the inane conceits of human curiosity. She asks rather for a kiss, that is, she calls upon the Holy Spirit by whom she is simultaneously awarded with the choice repast of knowledge and the seasoning of grace. . .
But knowledge which leads to self-importance, since it is devoid of love, cannot be the fruit of the kiss. Even those who have a zeal for God, but not according to knowledge, may not for any reason lay claim to that kiss. For the favor of the kiss bears with it a twofold gift, the light of knowledge and the fervor of devotion. He is in truth the Spirit of wisdom and insight, who, like the bee carrying its burden of wax and honey, is fully equipped with the power both of kindling the light of knowledge and infusing the delicious nurture of grace. Two kinds of people therefore may not consider themselves to have been gifted with the kiss, those who know the truth without loving it, and those who love it without understanding it; from which we conclude that this kiss leaves room neither for ignorance nor for lukewarmness.
From Sermon 8