Obedience is Needed for Spiritual Developgment

Obedience and a proper understanding of justification by faith are essential for cultivating a deep friendship with God. While biblical theology makes friendship with God possible, it requires us to treat God as He truly is, the Lord of the universe.

Obedience Cultivates Intimacy

You cannot simply have a feeling of closeness with God without the reality of obedience, just as you cannot have a deep friendship with someone if you constantly ignore who they are.

In any long-term friendship, friends inevitably rub off on one another; they begin to think alike, act alike, and converge in their character. This process is reciprocal in human friendships, but with God, it means we must move toward Him.

While Aristotle argued friendship with God was impossible because the gap was too wide, the Bible bridges this gap through the Image of God in humans and the Incarnation of Jesus. While Jesus moved toward us via the Incarnation, we move toward Him through obedience. This is how we become holy by adopting His character, loves, and hates. Without this movement (obedience), there is no convergence, and thus no deep friendship.

A key rule of friendship is letting the other person be themselves. You cannot be friends with someone if you are constantly trying to force them to be someone else. God is the Lord of the Universe. To be friends with Him, you must accept Him as He is. If you treat Him as an equal or a cosmic butler rather than as the Lord, you aren't being friends with the real God; you are creating a fantasy. Therefore, recognizing His Lordship through obedience is actually an act of respect and transparency required for the relationship to exist.

The Role of Justification by Faith Alone

Keller famously states that obedience is necessary for friendship, but he clarifies that this obedience must be driven by gratitude, not a desire to earn wages.

If you do not understand that you are saved by grace (justification by faith alone), your relationship with God will default to a mercenary one, like an employee and a boss. In a mercenary relationship, you do work (obedience/worship) and expect payment (blessings/answered prayers).

If a boss stops paying, the employee quits. Similarly, religious people who are mercenaries will abandon God when life gets hard or prayers aren't answered, saying, "I did my part, where is my payment?"  A true friend sticks around even when there is no benefit, simply because they love the person. Only the gospel, knowing you are already fully loved and paid for by Jesus, can create this kind of non-transactional heart.

The Law in the Sermon on the Mount and Psalm 1.  Both texts open their respective books (the Psalter and Jesus’ first major discourse in Matthew) with a promise of happiness and human flourishing. They both define the good life not by wealth or power, but by a person's relationship with God and His word., which says the godly person delights in the law of God. This sounds impossible if you look at the sheer weight of God's law, specifically Jesus’ Sermon on the Mount (where "do not kill" implies "do not hate"). Especially if you view the law as a way to earn salvation, it is terrifying and crushing because no one can keep it perfectly. It leads to despair, not delight.  

However, once you know Jesus has fulfilled the law for you (died the death you should have died, lived the life you should have lived), the law transforms. It is no longer a list of demands to avoid hell; it becomes a guidebook on how to please your friend. You obey not to get saved, but because you are saved and want to know what your Friend loves and hates.