From The Gospel of Matthew by Curtis Mitch and Edward Sri, commenting on the prayer in Matthew 11:25-27:
The final line of the prayer serves as a revelation to the reader. All things, Jesus says, have been given over to him from the Father. The meaning of this statement is not explained, but looking back over the Matthean storyline thus far, one may surmise that it refers to the divine authority that Jesus wields in the world. He possess teaching authority that ranks him above Moses (5:21–46); he displays healing authority to cure sicknesses and cast out demons in an instant (4:23; 8:3, 13–17; 9:22); and he is vested with spiritual authority to forgive the sins of others at will (9:1–8).