When Jesus was going up to the Heaven He command His disciples to not to leave the Jerusalem (Acts 1:4). Jesus wants them to "be there" and to wait for the promise of the Father (Joel 2:27-28; Act 2:17). Jesus don't want to empower them with old Power that Moses, Joshua, Judges and Daniel had. But Jesus wants to armed them with New Spirit / Power and for that Jesus told them to be there. 

     If you too need this new Spirit / Power, You should also needs to "be there" i.e. your Prayer Room and Church. Because they were all together in one place at the day of Pentecost and they filled (Acts 2:1-4).