In Rom 10.17, St Paul writes: "Faith comes through hearing, and hearing through the Word of Christ." Here's John Owen explaining how the Spirit is at work in us through preaching, not just to teach our minds but to strengthen faith and love in our hearts:
"We are greatly mistaken if we suppose we have no benefit by the Word beyond what we retain in our memories, though we should labor for that also. Our chief advantage lies in the excitation which is thereby given unto our faith and love to their proper exercise; and hereby are these graces kept alive, which without this [i.e. preaching] would decay and wither. Through preaching, the Holy Spirit 'takes the things of Christ and shows them unto us' (John 16.14-5). He represents them unto us in the preaching of the Word as the proper objects of our faith and love, and so brings to remembrance the things spoken by Christ (John 14.26); that is, in the dispensation of the Word, the Spirit reminds us of the gracious words and truths of Christ, proposing them to our faith and love. And herein lies the secret profiting and thriving of believers under the preaching of the gospel; which, it may be, they are not sensible of themselves."
- On the Holy Spirit, p. 389