Romans 7:6 (AMP) But now we are discharged from the Law and have terminated all intercourse with it, having died to what once restrained and held us captive. So now we serve not under [obedience to] the old code of written regulations, but [under obedience to the promptings] of the Spirit in newness [of life].

Walking in the Spirit is the power to live by God's Word, and not the dictates of your carnal mind!