Theme of chapter: Before ascending Jesus gives the apostles some final instructions about the Holy Ghost who was to come. After Jesus' ascends, Peter pipes up about getting a new 12th apostle, not being led by the Holy Spirit. They throw lots and Matthias wins out and becomes the 12th apostle. It could be argued that Paul is the real 12th apostle chosen by the Holy Spirit.
Most prominent word: bishoprick (office of responsibility; place of leadership)
Command to obey: be cleansed and renewed by the Holy Spirit daily by prayer and study of the bible.
New truth learned: The verse mentioned above deals with the great commission for believers. To take the word of God to; "Jerusalem" meaning your home town. "Judaea" meaning your neighborhood. "Samaria" meaning the wrong side of town, places you wouldn't go to. "uttermost part of the Earth" meaning ultimately taking the gospel to the whole world.