Musar zu Schemot 20:3

לא יהיה לך אלהים אחרים על פני. The verse not only discusses our conduct in this world, but also alludes to the Celestial Regions. On the one hand G–d forbids the worship of anything which is part of the עולם העשיה, our physical world, on the other hand worship of any beings, even in the Celestial Regions other than G–d Himself is equally forbidden. Nachmanides is quite explicit about all this in his commentary on this verse. Every angel found in the Celestial Regions is called Elohim and therefore falls under the category of forbidden deities.