The contemporary non-Christian legalist

Contemporary men and women are every bit as much "works driven" as their ancestors were, even if they fail to have the proper fear of God as judge. Indeed, they are even more burdened than people in the past for the very reason that they see themselves as their own judges. They carry the weight of establishing worth within themselves.

(p.187, Mark C. Mattes, The Role of Justification in Contemporary Theology)

Taking flight

Someone once said to me that faith and obedience are two wings of a bird - you need both to be saved.*

Not a good analogy.

I think it would be better to think of faith as the engine of a plane and the good works as the banner flowing behind which show the world that the plane is flying.

...perhaps you could do better though

*an interesting variation of John Stott's analogy for social action and evangelism.

Out -> inside -> out

Now, our Scholastics and papists have taught an external piety; they would command the eyes not to see, and the ears not to hear, and would put piety into our hearts from the outside. Ah, how far this is from the truth! But it comes in this way: When the heart and conscience cling to the Word in faith, they overflow in works, so that when the heart is holy, all the members become holy, and good works follow naturally.

(Easter Sunday Sermon: Of Christ's Resurrection, on Mark 16:1-8)

Martin Luther criticised an ethics which taught that by doing good things you could develop good habits that would filter down into your heart. He saw this ethics in Medieval Scholastic theology, but originating in Aristotle ("Virtually the entire Ethics of Aristotle is the worst enemy of grace. This in opposition to the scholastics" [Disputation Against Scholastic Theology, 1517]).

But that does not mean that he thought that personal change was a simple case of inside->out.

Our hearts are not changed spontaneously but in response to the external word, which could only be understood correctly by prayer, meditation and experience (Or Anfechtung, see his three rules).

Therefore, Bonhoeffer was standing in Luther's line when he explained that:

only the believers obey, and only the obedient believe.

It is really unfaithfulness to the Bible to have the first statement without the second. Only the believer obeys - we think we can understand that. Of course, obedience follows faith, the way good fruit comes from a good tree, we say. First there is faith, then obedience. If this meant only that faith alone justifies us and not deeds of obedience, then it is a firm and necessary precondition for everything else. But if it meant a chronological sequence, that faith would have to come first, to be later followed by obedience, then faith and obedience are torn apart...

space should be kept and had to be kept for that external deed required to enable faith - the step, in this case, to the church, where the word of salvation is preached... You can leave your house on Sunday and go to hear the preaching. If you do not do it, then you willfully exclude yourself from the place where faith is possible...

it is not the works which create faith. Instead, you are given a situation in which you can have faith.

(italics original, pp. 63-67, Dietrich Bonhoeffer, Discipleship)

[Note that as well as this 'religious work' he also gives examples of an alcoholic giving up alcohol or a rich man giving away his money]

[Note also that Bonhoeffer is not saying that the 'first step' is a 'good work', but that is a work, which allows space for faith, which leads to good works.]