What Is The Holy Ghost?
Simply put, the Holy Ghost is the Spirit of God. God is a spirit and is all around us, but is not in us until we are baptized with the Holy Ghost like the Bible tells us.
In the last day, that great day of the feast, Jesus stood and cried, saying, If any man thirst, let him come unto me, and drink. He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. (But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet given; because that Jesus was not yet glorified.) (John 7:37-39)
People first received the Holy Ghost after the death, burial and resurrection of Christ. Just before Jesus ascended up into heaven he spoke to his disciples...
And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me. For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence. When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel? And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power. But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. (Acts 1:4-8)
Receiving the Spirit was so vital that Christ commanded his disciples to not start preaching the gospel until they had been baptized with the Holy Ghost. The Holy Ghost would give them power to be witnesses unto the Lord and to carry the gospel to the ends of the earth.
When the Holy Ghost first fell on believers it was a spectacular event that caused quite a stir. Here's how Peter explained what was happening to the crowds around him:
But this is that which was spoken by the prophet Joel; And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: (Acts 2:16-18)
We are living in the last days and if there was ever a time we needed the Lord it's today. The Holy Ghost is that powerful, life-changing Spirit of God dwelling in us, causing us to walk in his ways according to his word. I can tell you from experience that I am a different person after receiving the Spirit. Have you received the Holy Ghost? If not ask the Lord for it.
And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you. For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened. If a son shall ask bread of any of you that is a father, will he give him a stone? or if he ask a fish, will he for a fish give him a serpent? Or if he shall ask an egg, will he offer him a scorpion? If ye then, being evil, know how to give good gifts unto your children: how much more shall your heavenly Father give the Holy Spirit to them that ask him?
Recommended Read: Praying In The Holy Ghost