To cite but one example from one section, consider what the Directory says about preaching doctrine from a text of Scripture:
In raising doctrines from the text, his care ought to be, First, That the matter be the truth of God. Secondly, That it be a truth contained in or grounded on that text, that the hearers may discern how God teacheth it from thence. Thirdly, That he chiefly insist upon those doctrines which are principally intended, and make most for the edification of the hearers.
These are wise words. It isn't enough that we preach what is true. That's certainly better than preaching what is false. But good preaching should be more careful and more arresting. We must also press home true doctrine for the edification of our hearers. Personal, passionate, pleading is what John Murray called it.
Just as importantly, we ought to preach what is true in the text we are considering and show our people where that truth is in that text. It is eminently true and edifying to remind our people of justification by faith or the inerrancy of Scripture or the exceeding sinfulness of sin, but we teach our people to read the Bible loosely when we consistently preach the right thing from the wrong texts. Preachers and teachers must stick closely to the text so that people can see the doctrine we are presenting is manifestly found in this text, and not just in our hearts, in our systematic theologies, or in our estimation of what would be best for people to hear.