…being filled with the fruits of righteousness which are by Jesus Christ, to the glory and praise of God.
All who are born again have been filled with the fruits of righteousness known as the fruit of the spirit revealed to us in Galatians 5:22-23. They are love, joy, peace, longsuffering, kindness, goodness, faithfulness, gentleness, and self-control. To bring that fruit to maturity we are told if we will walk in the Spirit we will not fulfill the desires of the flesh but will see theses fruits manifest.
Once you are born again your spirit being made new has all theses fruits within. That is why when we choose to live ruled by our spirit these fruits will be the result. One way we walk in the spirit happens when we become one with the Word of God. Jesus said His Word is Spirit. To become one with the Word we take time to read and meditate on scripture, especially the New Testament. As it begins to dominate us, we begin to walk in line with the Word of God.
A second key to walking in the spirit is to take the time to listen to the voice of your spirit known as your conscience. Before you speak or act if we take time to listen to this inward voice we will either have a check about doing what is not right, or a peace about what is right. This will lead to us obeying our spirit and the result will be the fruit of our spirit man. Walking in the fruits of righteousness will lead us to live a spirit lead life, dominated by our spirit and not our flesh.