Jesus said there is a promise of power for every Christian. When we become Christians, we are sealed by the Holy Spirit, who gives us a dimension of power that can radically transform our lives. But power to do what? It is power to be a witness. It is a practical power that can be used for the glory of God. It is power to give us courage to speak our convictions and stand up for our faith in Jesus Christ.
The word used for "power" in Acts 1:8 is the Greek word that gives us the word "dynamite." When Jesus said, "You shall receive power when the Holy Spirit has come upon you," He was saying that He would give us dynamic, explosive power to be witnesses for Him. This is something we receive when we ask the Lord to empower us with the Holy Spirit.
We are told in Ephesians 5:18 to "be filled with the Spirit." The word "fill" could also be translated to say, "It will permeate." God wants His Spirit to permeate every area of our lives. "Be filled" is a command; it is not just that we are doing a personal favor for God. This command applies to every believer, not just preachers or missionaries. And it means to be constantly filled again and again with the Holy Spirit.
The good news is that God gives refills, and it won't cost you anything. Isn't that nice to know? Just ask Him for another filling of the Holy Spirit.