Galatians 5:16 tells us that we are to walk in the Spirit because, by doing so, we will not give in to the works of the flesh. The works of the flesh, which are outlined in Galatians 5:17-21, are the things that will prevent those who practice them from inheriting the kingdom of God. But, when we instead live and walk in the Spirit, when we sow to the Spirit in our lives, we reap the ultimate harvest--everlasting life (1 John 6:8).
So, how do we live and walk in the Spirit? We do so by striving to become more like Jesus by cultivating the fruit of the Spirit in our lives. The fruit of the Spirit is love, joy, peace, patience or longsuffering, kindness, goodness, faithfulness, meekness or gentleness, and self-control. The desire of the Holy Spirit is to produce these in every believer.
The fruit of love is divine love, the kind of love that Jesus taught we should have for one another. When we have love like this, the other fruit become that much easier to cultivate in our lives. The fruit of joy is not the same as happiness. It is the joy that exists even in trials and tribulations. In that sense, it is much like the joy experienced by a mother when she sees her newborn child after having gone through the pains of labor (John 16:20-21).
Peace is the kind of peace that Jesus promises. It is a peace that surpasses all human understanding. Patience, or longsuffering, does not just mean being patient with others. It means persevering in our times of trouble. The fruit of kindness refers to the type of kindness shown by God, a kindness that is undeserved. We are called to show kindness even to our enemies.
Goodness is shown through integrity and moral living, as well as through doing good for others. Faithfulness, which has been shown to us in Christ's sacrifice for us, means being true to your word and to your obligations. Meekness, or gentleness, which are regarded as weakness by the world, mean demonstrating an inner strength in the face of difficult circumstances.
Finally, there is self-control. This is the fruit that holds all of the other fruit together. For example, if we love without restraint, it becomes passion. If we have patience without balance, it becomes apathy. Self-control provides the balance, restraint, and moderation needed by the other fruit.
To live and walk in the Spirit, all believers should seek to cultivate all of the fruit of the Spirit in their lives. When we do, we become more and more like Jesus, and that is God's will for all of us.