What is the 'Fruit of the Spirit'?
The 'Fruit of the Spirit' refers to the result of us coming to faith in Jesus Christ. Our outward appearance as it shows in our love and attitude for others. How we are perceived by others will be the result of us having in us the Holy Spirit or not;
"But the fruit of the Spirit is love, joy, peace, longsuffering, kindness, goodness, faithfulness," Gal. 5:22
Scripture is filled with many references to the 'fruit' that is produced. Although there can be a reference to 'bad fruit', we are assured that fruit of our labors is a direct result of the Holy Spirit that is within a true believer. If a person does not have this true faith, then it will be obvious by what they do, what they say, how they live their lives.
"Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravenous wolves. You will know them by their fruits. Do men gather grapes from thornbushes or figs from thistles? Even so, every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Therefore by their fruits you will know them." Mat. 7:15-20
So, again, the "fruit of the Spirit" is the result of our coming to faith in Jesus. Because the reality is, without Him we are capable of nothing;
"I am the vine, you are the branches. He who abides in Me, and I in him, bears much fruit; for without Me you can do nothing." John 15:5