At Pentecost, the Spirit of God transitioned from being present in a single place to being present with all believers. All anyone had to do to receive it was choose to follow Jesus. And then- they could carry it with them wherever they went. And they could share it- they could be witnesses to other people- beginning in Jerusalem, moving out to Judea and Samaria, and to the ends of the earth.
Pentecost is powerful picture of the new story Jesus followers were now part of. At a festival that connected them to their roots- God showed them the way forward. The believers put this new way into practice by loving one another well in community, sharing what they had with one another, eating meals together, and enjoying the favor of the other people around them.