It means that He must control the movement and direction of our lives. Our lives are now no longer our own but Christ's. Why do we think that we can receive Christ for salvation and then go on to live our lives as we choose? Salvation without the Spirit controlling our lives is not God's salvation but only a "cheap believism" which leaves us in our sins and doing what we think is right in our own eyes. In Biblical terms this is death (James 1:15). It is a life separate from Christ. Anything separate from Christ is sin. Christ is life and He has become our limits-those limits being light and life, not the realm of good and evil:
The Spirit has come to indwell that we might become partakers of His divine nature, and then that we might be changed into His likeness in expression. "Whereby He hath granted unto us His precious and exceeding great promises, that through these you may become partakers of the divine nature, having escaped the corruption that is in the world by lust" (2 Peter 1:4). These promises are the Savior, and the coming of the Spirit to indwell: "For unto us a child is born, unto us a son is given, and the government shall be upon His shoulder: and His name shall be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace" (Isaiah 9:6). "And it shall come to pass afterward, that I will pour out my Spirit upon all flesh, and your sons and daughters shall prophesy, your old men shall dream dreams, your young men shall see visions" (Joel 2:28).
"I indeed baptize you in water unto repentance: but He that cometh after me is mightier than I, whose shoes I am not worthy to bear: He shall baptize you in the Holy Spirit and in fire: whose fan is in His hand, and He will thoroughly cleanse His threshing-floor, and He will gather His wheat into the garner, but the chaff He will burn up with unquenchable fire" (Matthew 3:11-12). "And they that are in the flesh cannot please God. But ye are not in the flesh but in the Spirit, if so be that the Spirit of God dwelleth in you. But if any man hath not the Spirit of Christ, he is none of His" (Romans 8:8-9).