"I baptize you with water, but he will baptize you with the Holy Spirit."
What does it mean to be baptized with the Holy Spirit? The image here of baptism is one of full immersion. The Greek word baptizo means to submerge, dip, or immerse in water or the act of bathing or washing something by the same action. So then what does it mean to be baptized with the Holy Spirit? If we assume the visual to be the same, it means to be completely submerged and overwhelmed by the Holy Spirit.
The implications of this are huge. We are not talking about some ethereal power filling us up or some sort of mystical inner force. The Holy Spirit is a person, not some mysterious energy. More than that, He is God. Jesus Christ has come to not only be God with us, but to so completely immerse us in God that we are saturated and fully penetrated by him into every fiber of our being. As a sponge soaks up water, so our bodies will fill with the Holy Spirit.
And it changes us. God's eternal presence itself is what changes us. We are no longer dry and lifeless, but saturated with life. It is God who cleanses us by his very being. Jesus has come to baptize us with the Holy Spirit so that we too might experience the life of God forever and ever! Amen!