What is the ruling on one who says "Allah knows" while lying, and is that considered disbelief (kufr)? And is persistent indulgence in religious whisperings considered disbelief?

We ask Allah to grant you well-being from obsessive thoughts. We have already clarified that disbelief (kufr) does not occur by uttering the word "Uff" (تف). We advise you to turn away from these satanic whispers and not to yield to Satan regarding them, as this is the most effective cure for them. As for giving in to them, it is forbidden.