He came. He saw. He died and rose again. Now Jesus is planning on heading home to his Father in heaven, where we're guessing he'll get a pretty sweet welcome party. But before he bounces, Jesus has one more thing to do: pass the ministry torch onto his disciples.
All throughout the Gospel, Jesus says that he came mainly for the Jewish people. It's like he tells the Canaanite woman, "I was sent only to the lost sheep of the house of Israel" (15:24). Right. But that doesn't go so well in the end.
Now Jesus is looking to branch out. In the last lines of the Gospel, he gives one final command the remaining eleven in the posse: "Go therefore and make disciples of all nations" (28:19). That's all nations. Including the Gentiles. That's Matthew setting the stage for the future growth of the church right there.
The way Jesus presents himself here is also pretty interesting. He comes right out and says, "All authority in heaven and on earth has been given to me" (28:18). That's a lot of responsibility. It's quite different from the Jesus who dodges the messiah questions from high priests (26:64) and completely refuses to answer Pilate (27:14). Looks like the Resurrection really agrees with the guy.
Matthew's Gospel is the only one that features this "Great Commission" at the end. It's also the only one that instructs the disciples to baptize people "in the name of the Father and of the Son and of the Holy Spirit" (28:19). Fun fact: these are the words that are still used in most Christian baptisms today.
Way to make history, Matt.