What is the result of walking in the Spirit according to Galatians 5:16?
Walking in the Spirit means walking in the power and control of the Holy Spirit. The result is that the believer will not fulfill the lusts of the flesh; the Holy Spirit will not lead one to steal, commit adultery, or gossip, so the old Adamic nature's desires will not come to the fore.
Les explains that "Spirit" is capitalized, referring to the Holy Spirit. To walk in the Spirit is to walk in the power and control of the Holy Spirit. When He is operating and in control, the believer will not fulfill the lusts of the flesh. Les illustrates this by saying the Holy Spirit will never tell a believer to steal, commit adultery, or gossip. Those things still lurk in the background of the old Adamic nature, but if the Holy Spirit is in control, they will not come to the fore. In verse 17, Les notes Paul speaks of the flesh as the old Adamic nature, which lusteth or desireth—the word he likes for clarity is "wareth."
This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.