Luke 6:40 and the Theme of Likeness Education in the New Testament

What does Jesus mean when he says, A disciple is not above his teacher, but each disciple, after being fully trained, will be like his teacher (Luke 6:40)? This verse has been quoted, cited, and referenced in vast amounts of Christian education and discipleship literature. Nevertheless, the verse is nearly untouched in exegetical discussions with the exception of source-critical analyses. From thi...