His website -- Peterkreeft.com -- offers a generous helping of writings and audio recordings. And that's where I found his essay, Discernment, which leads off with the question asked in the title of this post. I found myself alternating between exclamations of "Amazing!" and "Well, of course!", always a sign that I'm in the presence of good thought and good writing.
Here's an excerpt, though I strongly encourage you to check out the whole thing:
Five general principles of discernment of God's will that apply to all questions about it, and therefore to our question too, are the following:
- Always begin with data, with what we know for sure. Judge the unknown by the known, the uncertain by the certain. Adam and Eve neglected that principle in Eden and ignored God's clear command and warning for the devil's promised pig in a poke
- Let your heart educate your mind. Let your love of God educate your reason in discerning his will. Jesus teaches this principle in John 7:17 to the Pharisees. (Would that certain Scripture scholars today would heed it!) They were asking how they could interpret his words, and he gave them the first principle of hermeneutics (the science of interpretation): "If your will were to do the will of my Father, you would understand my teaching." The saints understand the Bible better than the theologians, because they understand its primary author, God, by loving him with their whole heart and their whole mind.
- Have a soft heart but a hard head. We should be "wise as serpents and harmless as doves," sharp as a fox in thought but loyal as a dog in will and deed. Soft-heartedness does not excuse soft-headedness, and hard-headedness does not excuse hard-heartedness. In our hearts we should be "bleeding-heart liberals" and in our heads "stuck-in-the-mud conservatives." [Ed. note: Is this not the most delightful and incisive sentence you have read all day?]
- All God's signs should line up, by a kind of trigonometry. There are at least seven such signs: (1) Scripture, (2) church teaching, (3) human reason (which God created), (4) the appropriate situation, or circumstances (which he controls by his providence), (5) conscience, our innate sense of right and wrong, (6) our individual personal bent or desire or instincts, and (7) prayer. Test your choice by holding it up before God's face. If one of these seven voices says no, don't do it. If none say no, do it.
- Look for the fruits of the spirit, especially the first three: love, joy, and peace. If we are angry and anxious and worried, loveless and joyless and peaceless, we have no right to say we are sure of being securely in God's will. Discernment itself should not be a stiff, brittle, anxious thing, but—since it too is part of God's will for our lives—loving and joyful and peace-filled, more like a game than a war, more like writing love letters than taking final exams.