When the Bible speaks of walking in the Spirit, it’s sort of the opposite of walking in the flesh. Walking in the flesh is legalism (Galatians 1:8-9, 5:4). While this person want to obey and please God, he is doing so in the wrong way, because he’s focused on commandments, rules, and regulations.
Walking in the Spirit is the opposite of legalism. It starts each day with assurance that I have everlasting life by faith in Christ, apart from any works, and that there is nothing I can do to miss out on the kingdom (Galatians 3:1-4 and 5:1-4). Those who lack this certainty of their eternal destiny cannot walk in the Spirit because they will look to their works for assurance.
Walking in the Spirit means walking spiritually instead of carnally, like the legalists do. It means confessing one’s sins (1 John 1:9), because every believer sins on a daily basis, and asking the Spirit of God to take control. The staff at “Grace In Focus” recently illustrated this as follows:
“When a child is born into a family, that child will always be a child (positionally). However, when the child disobeys his earthly father, the child needs to set things straight if a harmonious relationship within the family is to be maintained (there needs to be daily forgiveness).”
It is the accumulation of God’s Word over months and years that the Spirit of God uses to transform us into the image of Christ (2 Corinthians 3:18). Since we all still possess the same fallen sin nature (the flesh), even after salvation (Romans 7:18), we need His daily guidance to overcome it.