Mark 3:13–19: Why Jesus Chose Twelve
Mark records Jesus' purpose for the twelve before it records their names: they were appointed to be with him and to be sent out. The number is not explained, but the choosing shows his will rather than their merit.
Why Jesus Appointed Twelve in Mark 3:13–19
Jesus appoints twelve men for two linked purposes: to be with him and to be sent out to preach with authority. The number twelve signals a people gathered around Jesus by his own call.