Miracle after miracle reinforced in the hearts of the disciples their own need to be filled with the Spirit. So when Jesus told His disciples to wait for the Holy Spirit, I’m sure they had a solid understanding of why they were told to do this as they remembered Jesus’ words: “You can do nothing without Me” (see John 15). The only way for them to do greater works than Jesus, as promised, was through the power of the Holy Spirit.
Whatever your interpretation of Scripture is on this point, please listen: Be filled with the Holy Spirit. The reason for this is because serving God is not like working for a company or a political party. It is not accomplished merely by using money and plans. With enough skills, drive and money, anybody can do that kind of work. But building something supernatural—that lasts for eternity—can only be done by supernatural power from the living God. So much of “Christian” work is one day going to be burned into a pinch of ash simply because it was a work of the flesh, not a work of the Spirit.
When I studied the book of Acts in college, it was all history and Greek and geography. But the book of Acts was not written so that we could study and get a degree out of it. It was written in order that we could know today, just like in biblical times, that we can be led by the Spirit of God and live this life by His power. Just like the early Church, we are meant to experience a life in which the Holy Spirit speaks to us, leads us and guides us today and every day.
So I encourage you to come before the Lord and ask Him to fill you with His Holy Spirit. Read about A.B. Simpson, Charles Spurgeon, A.W. Tozer, Andrew Murray or any of the saints like them. Each one had their own experience of being filled with the Holy Spirit, and it was a distinct experience, separate from salvation. It’s the promise He has given you. If you will but ask and yield, He will fill you with His streams of living water, and they will flow out of you to a thirsty and dying world, enabling you to live and serve in His power. But “without [Him] you can do nothing” (John 15:5).