The Fruit of the Spirit is the work of God to confirm us to the character of Christ. It is one big package that believers received upon the moment of conversion as the Holy Spirit regenerates our hearts to follow God. We see in Galatians 5:22-23, the first fruit is love.
To many, love seems to be the greatest attribute of the Christian faith. In the famous love chapter of the Bible (1 Corinthians 13), the Apostle Paul wrote, "So now faith, hope, and love abide, these three; but the greatest of these is love" (1 Corinthians 13:13). Paul says in his letter to the church in Colossae:
Put on then, as God's chosen ones, holy and beloved, compassionate hearts, kindness, humility, meekness, and patience, bearing with one another and, if one has a complaint against another, forgiving each other; as the Lord has forgiven you, so you also must forgive. And above all these put on love, which binds everything together in perfect harmony (Colossians 3:12-14).
The most famous verse in the Bible tells us how much God loves us:
For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life (John 3:16)
Romans tells that God shows his love for us that while we were still sinners, Christ died for us (Romans 5:8) and the result of that love is to show love for one another as 1 John 4:19 says, "We love because he first loved us." Love is also the evidence that we know God:
Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. Anyone who does not love does not know God, because God is love (1 John 4:7-8).
Jerry Bridges, in his book, The Fruitful Life, wrote, "Devotion to God is the only motivation acceptable to God for the development and exercise of Christian character. But devotion to God finds its outward expression in loving one another." We show the fruit of love by our loving one another. Yes, even those believers who may annoy you at times. Yes, it does include that child in your church that gives you raspberries just for the heck of it (then show mutual affection by giving one back).
1 John tells us that not loving one another is sign that you may not be a believer:
Whoever says he is in the light and hates his brother is still in darkness. Whoever loves his brother abides in the light, and in him there is no cause for stumbling. But whoever hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes (1 John 2:9-11).
God's work through His Holy Spirit produces love in the believer for one another. Love will cost us something whether it be time, money, or, at times, reputation. Jesus hung out with sinners and the religious leaders of His day thought He was a glutton and sinner just like them.
Love can be difficult at times especially if someone sins against you. 1 Peter 4:8 says, "Above all, keep loving one another earnestly, since love covers a multitude of sins." Christian, if you know someone you have a hard time loving because they have sinned against you, ask the Lord to forgive you and repent. Church keep on loving one another even if you may not agree with one another on secondary issues.
Believers, love those who do not know Jesus. God showed His love to mankind by sending His Son. We can show His love by being a friend to them and love them like Jesus would that we share the gospel with them.