"He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water." (John 7:38) Jesus was speaking in the temple, in fact, it was the last day of the feast. He spoke of that living water. Verse 39 tells us what he meant by that "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 7:39) Yes, that's the Holy Ghost, the third person of the Trinity. Since Jesus could not be everywhere at once in his human form, he knew that, besides being a sacrifice for our sins, he had to go back to heaven so the Holy Ghost could come which would allow his followers to perform the same miracles that he did. "Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you." (John 16:7) The Comforter is the Holy Ghost, or as some say, the Holy Spirit. He said earlier to his disciples, "Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father." (John 14:12) Has anyone done greater works? Well, we can read in Acts the following account. "And believers were the more added to the Lord, multitudes both of men and women.) Insomuch that they brought forth the sick into the streets, and laid them on beds and couches, that at the least the shadow of Peter passing by might overshadow some of them." (Acts 5:14-15) Some may argue that it doesn't say they actually got healed but the faith was so strong that I have no doubt that they did. Also, we read earlier that when the Holy Ghost first fell and Peter preached, 3,000 were saved, (Acts 2:41) and later 5,000 more after the crippled man was healed (Acts 4:4).
Now please don't misunderstand and think that I'm putting the Holy Ghost ahead of our Lord Jesus Christ. NO NEVER! Jesus is the Author and Finisher of our faith (Hebrews 12:2) and without Him there would be no Holy Ghost. But I'm trying to show you the love he showed for us in that he not only died for our sins, but he left us power here on the earth after he ascended to heaven. His last command to his disciples was "that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me." (Acts 1:4b) The reason was explained in verse 8, "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."
The Holy Ghost gives us power to preach and proclaim God's Word. Not only that, we have the nine gifts of the Spirit available as we believe and obey Him. Does God fill with the Holy Ghost today? He sure does and he does it with the evidence with the speaking of other tongues. "For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call." (Acts 2:39) It IS for today.
Now God will fill anyone who is saved by the blood of Christ and walking in obedience to His Word. Maybe you are reading this and want filled with the Holy Ghost but haven't gotten it yet. There could be several reasons why.
1. You should examine yourself to see if you are obeying God and his Word. If your conscience is bothered about something, it will shut off the spirit in your life and you will not get it. 2. You may be trying too hard. Just relax and believe that God will fill you. CAUTION: Do not let anyone try to "teach" you how to talk in tongues as that is not of God. God can fill and will fill for those who believe. 3. Maybe you have those around who are are doubters. While you may not be able to completely exclude yourself from them, try not to listen to them. 4. You may need to take some scriptures and stand on them. Some of the ones given above would be good to start with but there are many others. Dig them out. 5. Maybe you need to fast a day or two to show God you are really serious about wanting the Holy Ghost.
At any rate, God has not lost his power nor is his promises slack. It's our lack of faith that stands in the way. Remember the following scripture. "But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him." (Hebrews 11:6)