If you were in the midst of thousands of people and you wanted to address the crowd, how could you get their attention? Why would they stop and listen to you? Peter, an obscure Galilean fisherman, was given the opportunity to address thousands when the Holy Spirit descended in tongues of fire (Acts 2:3) and a miracle occurred when each of the thousands heard the Pentecostal proclamations in his own tongue. Then Peter had a forum to address thousands.
How would this ever happen again and again? Peter, in the name of Jesus, healed a man who was lame from birth. "He jumped up, stood for a moment, then began to walk around. He went into the temple with them — walking, jumping about, and praising God" (Acts 3:8). Peter again had an audience of thousands.
The risen Lord has commanded us to be His witnesses, and He will provide us with all the opportunities necessary. If we are called to address large crowds as was Peter, the Lord will take something and turn it into a media event. We need only obey Him in the details of our everyday, risen life.
Possibly, the Lord is not calling us to directly reach large crowds but to reach those especially resistant to the resurrection message. The Lord will somehow crack the door of their resistance. Because the risen Lord has called us to be His witnesses, He will create the necessary forums. Our job is to be faithful in daily, detailed obedience to Him and to be courageous as His witnesses.