The source

“Earlier in his letter to the Galatians, before taking up the fruit of the Spirit, Paul asks this rhetorical question: 'Having begun in the Spirit, are you now being made perfect by the flesh?' (3:3). In Galatians 5:25 he says, 'If we live in the Spirit, let us also walk in the Spirit.' Paul is leading us to understand that our Christian maturation and fruitfulness do not happen at any point by self-effort to turn over a new leaf. Rather, we are dependent on the operation of the Holy Spirit.”— Vine Ripened Life

<idle musing>
If only we would remember that! It is the Holy Spirit, living within us, motivating us, directing us, gently prodding us—OK, sometimes not so gently!—that produces Christian character. The fruit of the Spirit is named that for a reason! It isn't the fruit of my spiritual maturity or my efforts at godly living!
</idle musing>