The testimony of the early believers was that they had received and were filled with the Holy Ghost. Today also, we must have the Holy Ghost, to give witness of the life of God and to be able to do a spiritual work. The early disciples not only spoke by the Holy Ghost, but also were directed by the Holy Ghost. Men were sent out to do the work of God by the direction of the Holy Ghost (Acts 13:2). Approval was given by the Holy Ghost (Acts 15:28).
Paul was stopped from going to Asia and Bithynia by the Holy Ghost. The Holy Ghost appointed men to be overseers (Acts 20:28). The Holy Ghost was in control in the church spoken of in Acts, and He is still in control in the church today. Paul tells us, "For as many as are led by the Spirit of God, they are the sons of God."
"The Spirit itself beareth witness with our spirit, that we are the children of God" (Romans 8:16).
"...Even so the things of God knoweth no man, but the Spirit of God" (I Corinthians 2:11b).
"For the fruit of the Spirit is in all goodness and righteousness and truth: proving what is acceptable unto the Lord" (Ephesians 5:9,10).
"And grieve not the Holy Spirit of God, whereby ye are sealed unto the day of redemption" (Ephesians 4:30).
If you have come to the place of faith in God, and you believe that the baptism in the Holy Ghost is for you, now start to put your faith in God's Word. Luke 11:9-13 tells us what to do, "Ask, and it shall be given you; seek, and ye shall find: knock, and it shall be opened unto you. For everyone 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 to your children; how much more shall your heavenly Father give the Holy Spirit to them that ask Him?"
Now you must ask in faith, believing that you will receive. Allow God to give you heavenly evidence. Acts 2:4 says that "they spoke as the Spirit gave them utterance." Tongues are God's evidence given by the Spirit (I Corinthians 12:7,10). Diverse kinds of tongues are a manifestation of the Spirit.
"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 7:38,39).