Note 5 at Acts 4:31: The disciples had already been filled with the Holy Ghost (Acts 2:4), so what was happening here? The Holy Spirit resides in our spirit and once He comes, He doesn't leave (Jn. 14:16). There is an initial filling when the Holy Ghost first comes and that is what the disciples experienced on the day of Pentecost.

However, His control and influence over our soul and body does fluctuate proportionally to how well we have our minds renewed to His will (Rom. 12:2). In that sense, we can be more full of the Holy Ghost than at other times, although in our spirits the presence and power of the Holy Spirit does not come and go. Therefore, even after we receive the baptism of the Holy Ghost, there will be times when our soul and body stray from the leadership of the Holy Spirit and we need, once again, to be filled with the Holy Spirit.