"I ask you to tell me, of whom...?" To know that the prophets sometimes speak about others as well, or about themselves in another person, because this is what his question shows — the quality of a very observant man.
"Behold, water; what hinders me from being baptized?" See how prudently he acts. First he reads and does not understand, then he reads the same prophecy; it contains the teaching about the suffering, the resurrection of Jesus Christ, and the bestowal of the grace of the Holy Spirit. Then he asks to be baptized; Philip explains to him in order, beginning from this prophecy. And having been uplifted by his readiness, he is gradually led to baptism. But he did not say "baptize me," but rather: "what hinders me?" By this question he showed a strong desire to receive baptism.
"An Angel of the Lord caught Philip away." An Angel takes him, thereby adding greater wonderousness to what had happened, and at the same time bringing joy to Philip as well, that he was deemed worthy of the same things as the prophets, such as Habakkuk. It was good that he was taken from the eunuch, because the eunuch would have asked Philip to go with him, and Philip would have grieved him if he had refused due to the demands of circumstances. Thus everything was arranged in a divine manner: Philip found himself in Azotus. It was here that he was then to preach.