In Jesus' ascension in Acts 1 he says "and you will be my witnesses". In the Great commission he commands us to disciple by way of going, baptizing and teaching us to observe everything he commanded. At Pentecost he gave us the Holy Spirit to move through us that this would happen. So what do we do now? We're going to spend a number of weeks in the Sermon on the Mount, the most famous "Greatest Hits" section of teachings that Jesus gave.