Today I was crossing the street on foot at the intersection of 21st Street and Garnett. This is a fairly busy intersection, with three lanes of traffic coming from every direction. I didn't just walk out into the street; first I pressed the button to get the "walk" signal, and then I waited until I saw the indicator light up that said that it was my turn to walk across the street. When I stepped out into the street, all the cars stopped for me. I didn't even have to raise a hand; they just stopped. Was it because they saw me coming? Nope; it wasn't my power that stopped them. It was the power of the rule that says when the light is red, you stop your car and wait. Because I was following a signal and rule as well, the "walk" sign, I was confident that I could walk safely across. I didn't have to run or be afraid of getting run over. (Of course, it's wise to be cautious and still look both ways before crossing! But for the sake of argument let's pretend that all drivers are completely competent and always paying attention.)
The Holy Spirit is our signal that we can move in the power of God. He is a deposit placed on the inside of us that tells us that when we move by His prompting, we can have confidence not only to come into the presence of God, but to do His works on the Earth. The Holy Spirit is the signal (like my "walk" sign) that lets us know that the power of God is our protection when we do something that might ordinarily be dangerous (like walking calmly out into the street at a busy intersection). If I had walked out into the street without the signal, I would have been in terrible danger. But when I walked out with the proper signal, I walked out in confidence and safety. And when I move by the prompting of the Holy Spirit, I can walk in confidence and safety, because I know that the power of God is infinitely greater than the power of a traffic light. If I can trust a traffic light to keep me safe from a couple of automobiles, how much more can I trust God to keep me safe from anything in the universe that would try to stop or harm me?