He Will Baptize You With The Holy Spirit (Mark 1:8)

"I indeed baptized you with water, but He will baptize you with the Holy Spirit." ~ John the Baptist (Mark 1:8)

We, in the New Testament era, have the privilege of a blessing that those in the Old didn't have - the baptism of the Holy Spirit. What a Loss if we lose sight of this blessing, to have it and to walk in its fullness everyday!

I believe that it is the enemy's no.1 plan to keep Christians from living in the fullness of the Spirit daily. He is not bothered so much with their looking back again and again to the Old Testament and being satisfied only with the waters of the baptism of repentance. But, he would not want Christians to desire the same experience that the early church had in the Book of Acts. The result: a very shallow life of carnality, bondage and lack of freedom.
Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom (2Co 3:17 NIV)
The Holy Spirit is the greatest blessing of the New Covenant. In fact, He is called the Promise of the Father! The people in the Old Testament looked forward to it, but they didn't have the blessing. The Spirit came and left in those days; and, He only came upon some specific people. But, the blessing is given to us in the New Testament through Jesus Christ, the One Who Baptizes us with the Holy Spirit.
He commanded them not to depart from Jerusalem, but to wait for the Promise of the Father, "which," He said, "you have heard from Me; "for John truly baptized with water, but you shall be baptized with the Holy Spirit not many days from now." (Act 1:4-5)
Didn't the Father promise?
And it shall come to pass afterward That I will pour out My Spirit on all flesh; Your sons and your daughters shall prophesy, Your old men shall dream dreams, Your young men shall see visions. And also on My menservants and on My maidservants I will pour out My Spirit in those days. (Joel 2:28-29 NKJ)
And, the Promise was not just for the 120 disciples in the Upper Room; it was for all, for all nations:
Then Peter said to them, "Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit. For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call." (Act 2:38-39)
Certainly, this doesn't just mean "for 1st century Christians"; for, if the promise was also for "all who are afar off", there are still people "afar off" who have still not been reached with the message of the Gospel. Mark tells us that this was what John the Baptist went about preaching (as we saw in Mark 1:8); and note, John wasn't preaching to the Twelve Apostles, he was preaching to all.

The Apostle Paul tells us that the Holy Spirit is the Blessing of Abraham.
Christ has redeemed us from the curse of the law, having become a curse for us (for it is written, "Cursed is everyone who hangs on a tree1 "), that the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith. (Gal 3:13-14)
The same signs that the Apostles and the brethren in the Upper Room had in Acts 2 is what accompanies the baptism of the Spirit even today.
they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance (Act 2:4)
The following story recounts how Smith Wigglesworth, an ordinary plumber, became filled with the Spirit. Later, God used him mightily to win many souls to Christ, to heal the lame, the blind, and the deaf and to raise many people from the dead.
At about 11 a.m., Tuesday morning, at All Saints’ Vicarage, I asked a sister to help me to the witness of the Baptism of the Holy Ghost. She laid hands on me in the presence of a brother.
The fire fell and burned in me till the Holy Spirit clearly revealed absolute purity before God. At this point she was called out of the room, and during her absence a marvellous revelation took place, my body became fill1 of light and Holy Presence, and in the revelation I saw an empty Cross and at the same time the Jesus I loved and adored crowned in the Glory in a Reigning Position. The glorious remembrance of these moments is beyond my expression to give-when I could not find words to express, then an irresistible Power filled me and moved my being till I found to my glorious astonishment I was speaking in other tongues clearly. After this a burning love for everybody filled my soul. I am overjoyed in giving my testimony, praying for those that fight this truth, but I am clearly given to understand that I must come out of every unbelieving element. I am already witness of signs following. Praise Him. (Smith Wigglesworth)

Here is another account from a great servant of God in India, Kurien Thomas, whom God used to raise scores of missionaries and leaders in India:
I sat quietly with my hands folded in prayer, in a reverent and orderly fashion. Then the old pastor's wife started to speak to me in the Spirit. She revealed many things about my life which no one but myself could have known. The doubts I had about the Pentecostal experience began to fade. Instead, I began to thirst for the anointing of God's Holy Spirit. With this deep, heart-felt desire I began to pray.
One evening, after the prayer meeting had ended, I went to the home of some believers. Many of God's children were present including some pastors, and we began to pray. The midnight hour passed; then at about 2 a.m., as I was on my knees in prayer, God spoke to me, "Son, I am going to give you the power of the Holy Spirit. What are you going to do with this power?" I bowed in full surrender to my Lord. Then I said, "Lord, give me this power and by this power I will serve you. I will live, not for the kingdoms of this world, which must soon pass away, but for your eternal Kingdom and I will serve you in this land of India."
Having prayed this prayer of dedication I stood up and told the whole company what had happened. As I sat down again, I was suddenly overwhelmed by an unseen power and thrown to the floor. I began to thank and praise the Lord for the gift of His Holy Spirit. People watching me saw that I was covered with a heavenly light, aglow with the Glory of God! I began to praise God in other tongues and from 2 a.m. through until 10 a.m. I could not stop speaking in this new language. (Kurien Thomas, God's Trailblazer)
Jesus said that when we are baptized with the Holy Spirit, we receive power to be His witnesses (Acts 1:8).
"But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem, and in all Judea and Samaria, and to the end of the earth." (Act 1:8)
But, the Baptism of the Holy Spirit is a single-event. We must also live in the fullness of the Spirit, and be filled with Him and His power like the the early church did, again and again, continuously.
And when they had prayed, the place where they were assembled together was shaken; and they were all filled with the Holy Spirit, and they spoke the word of God with boldness. (Act 4:31)
...be filled with the Spirit, (Eph 5:18)
The Bible teaches us (and do we listen?) that anyone who prays in tongue edifies himself, because it is the spirit that prays though one cannot understand the words with the mind. The spirit speaks the mysteries of God.
He who speaks in a tongue edifies himself (1Co 14:4)
...if I pray in a tongue, my spirit prays, but my understanding is unfruitful. (1Co 14:14)
For he who speaks in a tongue does not speak to men but to God, for no one understands him; however, in the spirit he speaks mysteries. (1Co 14:2)
Isn't that wonderful? It means that the human spirit that is born-again and regenerated by the Holy Spirit knows the mysteries of God, but our natural mind (psuchikos, psychological) can become a hindrance, because it is still not renewed.
But the natural (psuchikos) man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them, because they are spiritually discerned. (1Co 2:14)
Therefore, Paul encourages us to pray with the spirit (i.e. in tongues) in our private prayer (but, only with interpretation for understanding in corporate gatherings):
I thank my God I speak with tongues more than you all; yet in the church I would rather speak five words with my understanding, that I may teach others also, than ten thousand words in a tongue. (1Co 14:18-19)
Much can be said on this topic, but I believe the most important thing that God wants us to understand today is that He wants us to be filled with the blessing of the Holy Spirit, the Promise of the New Covenant, the Promise of the Father, and He wants us to live and walk in the fullness and edification of the Holy Spirit.