If they intended by the partners their deities, then the meaning of 'Our partners' is our deities that we called partners. And if they intended the devils, it is because they are their partners in disbelief and their companions in misguidance: and 'we call upon' means 'we worship.' If you say: Why did they say 'Indeed, you are liars' while they were worshiping them correctly? I say: Because they were not pleased with their worship, it is as if their worship was not worship. The evidence for this is the saying of the angels: 'They used to worship the jinn,' meaning that the jinn were pleased with their worship, not us; they are the ones being worshiped, not us. Or they lied about them in calling them partners and deities, glorifying Allah from having a partner. And if the partners are intended to be the devils, it is possible that they were 'liars' in their saying 'Indeed, you are liars,' just as the devil says: 'I have disbelieved in what you associated with me before,' and they cast away, meaning those who wronged. And casting away submission means surrendering to the command of Allah and His judgment after refusing and being arrogant in this world, and what they used to invent has failed them, that Allah has partners, and that they support them and intercede for them when they lied about them and disavowed them.