Hosea 4:6
My people are destroyed for lack of knowledge.
Because you have rejected knowledge,
I will reject you from serving as My priest.
Since you have forgotten the law of your God,
I will also forget your sons.
Here, the angel who had one of the seven last plagues came to John to reveal the outcome of the prostitute which in Scripture refers to a group of people claiming to be from God but in actuality is teaching false doctrine.