What is the ruling on internalizing disbelief without uttering it or believing in it?

One is not held accountable for inner thoughts of disbelief that occur without intention or the heart's approval, as Allah says: "Our Lord, do not impose blame upon us if we have forgotten or erred," and as the Prophet, peace and blessings be upon him, said: "Indeed, Allah has forgiven my Ummah for whatever thoughts cross their minds, as long as they do not act upon them or speak them." It is incumbent upon anyone experiencing such obsessive thoughts to seek refuge in Allah from the accursed Satan.