Back in the 8th century BC this first reading is for Isaiah a vision and a hope based on his understanding of God and His relationship with this world. It is expressed by the prophet as best as he can as being like a dream for an ideal king, a descendant of David (son of Jesse), with wonderful gifts of spirit, like wisdom, empathy, understanding and respect for God. But also a dream of an unimaginable peace, even in nature and between humans and animals – in our eyes an impossible world. In addition, again “on that day” it is written, this peace will extend even to the Gentiles – more asily imaginable to most of us here and now, with in our understanding of God’s universal love.
The second reading (Rom 15:4-9) is part of the conclusion of Paul’s long letter to the Romans. It is calling for harmony, a lesson that can be learnt from Scripture (which for Paul means what we call the Old Testament) but we can learn from the New Testament. God not only became one of us, but also, for the sake of the Jews, was under their Law and all that entailed; but this self-abasement was so as to live (and die) for all people and thus give glory to God. However, Paul quotes the end of a song of king David (2 Sam 22:47-50) who ruled over many nations whom he had conquered by force.
Before today’s gospel reading from Matthew (Mt 3:1-12) he has written about the genealogy, the birth with its announcement to the shepherds and the incidents surrounding the magi with their gifts. But now the preaching of the kingdom begins with John the Baptist; it is a topic found also in the other gospels; but unlike Luke and Mark, Matthew has John straight away preaching the very message of Jesus “Repent for the kingdom of heaven is at hand.” A significant word for us is ‘repent;’ it means in the Greek a change of mind, and for us a change of our way of life. Most noticeable also is the vituperative language used against both the Pharisees and the Sadducees, and the suggestion that physical descent from Abraham is not an assurance of acceptance by God; so we too, if we live aright, will be within the reign of God. Then we hear John announce the coming of Jesus into public life, and who will sort things out; a process like harvesting grain – removing and burning the chaff. And it is a baptism that is the sign of this commitment, even needed for Jews; though this is not the same as Christian Baptism, but is a washing symbolic of the change of life preached with the word “repent!” It may be that the phrase “In those days” which begins the gospel reading, rather than just meaning something like ‘then,’ actually means this new time of the kingdom in which we, today, live.
See Jeffs Jottings – Change