What is the Baptism in the Holy Spirit
Baptism in the Holy Spirit is not a new sacrament but rather an awakening of the graces of Baptism and Confirmation. It renews our Christian initiation. Most of us were baptized as babies. We received the Holy Spirit but we need to consciously respond with our personal assent to Him, giving the Lord full authority over our lives. Baptism is God's gift but, if we do not respond to it through faith, it remains dormant.  

"...but one is coming after me who is mightier than I... He will baptize you with the Holy Spirit and fire!"  -Mt 3:11

Fr. Cantalamessa: “such grace (Baptism in the Holy Spirit) is related to baptism, because God acts always with coherence and faithfulness and He does not do and undo. He honors the commitments and institutions of Christ.”

Early Church: Adult baptism.
Each person responded in faith. Chose to renounce to all, to be persecuted for Christ.
The mistagogic catechesis on baptism attributed to Cyril of Jerusalem show the depth of faith and conversion to which those waiting for baptism were led.
Grace + an act of faith, free and mature choice.

Therefore their baptism manifested the powerful presence of the Spirit because the grace of God and man's full response met at the same time. St Ciprian wrote about becoming “A new man.”

Today : Infant baptism
Profession of faith done by parents and godparents.
We did not respond with a free personal act of faith at time of baptism
Maybe we began to respond as we grew up.
But Christianity is often reduced to obserbing the law.
Few realize the full experience of the HS because even in most Christian environments it is no longer known.
Few expect to experience Pentecost.

We tend to limit God in His freedom:
Fr. Cantalamessa: “we tend to insist that He follows a pattern (channels of grace) and we forget that God is a torrent that breaks loose and creates its own path and that the Spirit blows where and how he wants (notwithstanding the role of the teaching of the Church to discern what actually comes from the Spirit and what does not come from Him).

Jesus in Nazareth: "could not perform many miracles because of their lack of faith." (Mt 13. 58)

Ben XVI "...even if we were baptized as children, we must enter into the reality of our baptism; throughout our lives"

Who imparts it
It is not the brothers who impart the Holy Spirit, but they do invoke the Holy Spirit on the person. Only Jesus may give the Holy Spirit; all the others do not possess the Holy Spirit, but rather are possessed by Him. The community part: 1 brotherly love, 2 faith, 3 laying on of hands, 4 prayer.

The principal fruit of the baptism in the Holy Spirit is to come into a deep relationship with Jesus in the power of the Holy Spirit and therefore a desire to respond to Him giving ourselves completely to the Father. Living fully the Christian life; hunger for the Word, for the Eucharist, love for the Church, love for all, service, renewed appreciation of our vocation, greater involvement in evangelization.

Courage. Not be afraid of what others may think. What problems it may bring us.
Benedict XVI: “Every irruption of the Holy Spirit always upsets human plans”.

We will continue to be weak, need to cling to the Lord. Ben XVI: “the Spirit works through human beings and does not simply free them from their weaknesses” St. Paul: I am happy to make of my weaknesses my special boast...

But we need to be OPEN
Repentance: Recognize that we have been in control: efforts, organization, reforms. We think it is normal to manage God's power.
Humility. To beg and to submit to the Holy Spirit.

A "bound" Sacrament
Fr Raniero Cantalamessa: "Catholic theology recognizes the concept of a valid but "bound" sacrament. A Sacrament is bound if the fruit that should accompany it remains tied because of certain blocks that prevent its effectiveness. The effectiveness of the sacrament is the result of a cooperation between the grace of the Holy Spirit and human freedom. God pours out the grace of the sacrament in our lives, but the full actualization of our Baptism comes about only through our own personal “yes,” our response of faith, to His divine grace." 

Example: the Sacrament of Matrimony received in the state of mortal sin. In such circumstances the sacrament may be valid but cannot grant any grace until the obstacle of sin is removed through penance. Once this happens, the graces of the sacrament can flow thanks to the indelible character and irrevocability of the gift of God: God remains faithful even if we are unfaithful because He cannot deny Himself (see Timothy 2:13).

Baptism too is often tied : St. Augustine: "The one who created you without your cooperation, will not save without your cooperation."

God's grace is the "opus operatum" in baptism. It includes forgiveness of sins, the gift of the theological virtues of faith, hope, and charity (these, however, only as a seed), and divine sonship. 

But man´s part, the "opus operantis" in baptism is also needed. It consists of faith. "Whoever believes and is baptized shall be saved" (Mark 16:16). "To all who received Him He gave the power to become children of God: to those who believe in His name" (John 1:13).

The effectiveness of the Baptism of the Holy Spirit is that finally man contributes his part: He repents, makes a choice of faith.

Baptism in the Holy Spirit is also a renewal of our Confirmation because it is a deliberate "yes" to our baptism, to its fruit and its commitments. Confirmation being the sacrament that develops, confirms, and brings to completion the work of baptism.

US Bishops
"Baptism in the Holy Spirit makes Jesus Christ known and loved as Lord and Savior and through inner transformation affects the whole of the Christian's life" -U.S. Conference of Catholic Bishops "Grace for the New Springtime"