After resurrection, at the ascension, there is the command to go out and tell. It is Pentecost when the disciples are enabled to obey. By in large, for us too, there the command but we are not good at telling others. Peter attributes this to the relentless attack on the Christian church since the Enlightenment and the fact that we cannot do God's work unaided by Him. So Peter encourages us to ask for the empowering of the Holy Spirit to enable us in our callings.