In the remainder of the chapter, 14 verses, we see the disciples groping about for how to advance the mission by the appointment of another apostle. Dr. Luke directs our attention to the active witness-seeking and preparation the disciples undertake. It's a process undergirded by prayer and an earnest desire that God raise up witnesses to Jesus' life, death, and resurrection.
Let me ask you this: is your church focused only on teaching those that have come in the door? Are they hoping for a repristinated past where Christianity had a certain cultural cache? Or are they standing around looking up at the sky waiting for something to happen?
The replacement of Judas by St. Matthias gives us an example. Power had been promised for the task of witness...but it hadn't shown up yet. Nevertheless, the disciples were praying earnestly for that power and making all the provisions necessary to be witnesses immediately. Is that what your church is doing? If not...why?