The mentality behind the fruit of the Spirit is the mentality of faith depending upon grace. People who bear the fruit of the Spirit know they are worthy only of condemnation. They know that the only pay they can earn is the wrath of God. Therefore, they have turned away from self-reliance and look only to mercy in Christ who “loved us and gave Himself for us” (Gal. 2:20). They do not expect anyone to be their debtor because of their worth. Any satisfaction will be a free gift of grace. They bank on the mercy of God and entrust themselves to his Spirit for help. And out of that mentality of faith depending on grace grows not “works” but “fruit”: love, joy, peace, patience, kindness...
John Piper