In my book The Eternal Childhood of the Believer, I told the story of Brooke Greenberg, a girl who lived to be twenty years old but whose body and mind never developed beyond that of a toddler. Doctors were baffled. Despite the passage of time, her body seemed frozen in childhood. Her cells aged, but her development didn’t. Her condition was called "Syndrome X"—an incredibly rare and mysterious disorder. But for me, her story became a powerful metaphor.

Too many believers live out a spiritual version of Brooke’s condition. They may have known Jesus for years—decades even—but their spiritual growth stalled somewhere along the way. They may attend church, know Bible stories, and even serve in ministry, but they remain immature in character, shallow in faith, and lacking the fruit that God intended.

This book is about growing up.

It’s about refusing to stay stuck.

It’s about climbing.

It’s about becoming love.

Becoming Love

Peter’s list ends where the Christian life ultimately aims:

…and to mutual affection, love. — 2 Peter 1:7

Love is not just one of many virtues. It is the goal. The capstone. The final step in the ladder of spiritual maturity. Everything that comes before it—faith, goodness, knowledge, self-control, perseverance, godliness, and mutual affection—leads to love. And everything that comes after it flows from love.

Love is what we’re becoming.

• You can have faith that moves mountains, but without love, you’re nothing (1 Corinthians 13:2).
• You can have all knowledge and speak in tongues, but without love, you’re just noise (1 Corinthians 13:1).
• You can serve sacrificially, but if love isn’t the motive, it gains you nothing (1 Corinthians 13:3).

Love isn’t a decoration on the Christian life. It is the very definition of spiritual maturity.

Why Love Comes Last

It’s tempting to think that love should come first—after all, Jesus said the greatest command is to love. But Peter wisely puts it last, not because it’s least important, but because it’s the most advanced.

You don’t start at the top of the ladder—you climb to it.

Love is not shallow. It’s not sentimental.

It’s hard. It’s costly. It requires the full weight of everything that comes before it:

• Faith, because love takes trust in God to love people who may never love you back.
• Goodness, because love always chooses what is right, not just what is easy.
• Knowledge, because love needs wisdom to know how to act in complex situations.
• Self-control, because love holds back its own desires for the sake of others.
• Perseverance, because love keeps going when people disappoint or hurt you.
• Godliness, because love flows out of reverence for God and His image in others.
• Mutual affection, because love begins in the relationships closest to us.

Only when these qualities are in place—growing, stretching, deepening—do we become the kind of person who can love like Jesus.

Love Is the Destination, and the Evidence

When Peter says “make every effort” to grow in these virtues, he’s not just giving us a moral upgrade plan. He’s pointing us toward a completely transformed heart—a heart that no longer revolves around self, but around God and others.

That kind of heart expresses itself in one way: love.

Love is the destination. But it’s also the evidence that we’ve been walking with Jesus. It’s how the world knows we belong to Him (John 13:35). It’s how we know the Spirit is at work within us (Galatians 5:22). It’s how we measure whether all our spiritual growth is real.