What does Matthew 12:19 mean?

Matthew is quoting a version of Isaiah 42 and applying it to Jesus. The original passage was, it would seem, written about Israel. Under the inspiration of the Spirit, though, Matthew shows how Jesus has fulfilled the prophecy. Jesus is sometimes called the perfect Israel or the ultimate Israel. He is the best and fullest example of God's chosen people.

The passage in Isaiah is describing this servant with whom God is pleased and on whom the Father has placed His Spirit (Isaiah 42:1–3). The servant's work will eventually be to proclaim justice to those who are not Israel, the Gentile nations.

Now Isaiah adds that the servant will not quarrel or cry out. Nobody will hear His voice in the streets. In other words, the servant is gentle and humble, not putting effort into calling attention to Himself. This was true of Jesus, as well. He taught publicly and He healed many people, but He avoided conflict with His enemies when it was prudent (Matthew 12:15) and warned His followers not to publicize His miracles (Matthew 12:16). Still, the crowds grew. Jesus did not have to engage in self-promotion to draw people to His words and deeds.