"In 2:1-4, in other words, the author casts the angels in a positive, though inferior, role.1 This positive role is basic to the rhetorical argument that the hearers need to take seriously the revelation delivered through the Son, so the answer to our questions "Why the angels?" has nothing to do with the worship of them and everything to do with the execution of a skillful argument on the part of our author. To be sure, the listeners had a high regard for and interest in angels, as did others from a worship orientation in Greek-speaking Judaism. At this time Jews placed a great emphasis on angels as intermediaries between God and people. They were seen as exalted beings who functioned as heavenly emissaries. This fact makes the rhetorical argument all the more powerful. The audience's respect for the role of angels provided a reference point from which to speak of the much higher position (and, therefore, authority) of the Son of God. In this insight on finds the author's purpose for 1:5-14: The preacher wishes to impress on his listeners the Son's supreme unequivocal authority."
1 Lane, Hebrews 1-8, p. 17
The NIV Application Commentary, p. 72