What is the ruling on the whispers that afflict a young man concerning purity, jinn, and creed, especially when the whispers about creed intensify despite his continuous performance of remembrance (dhikr) and prayer? Are these thoughts considered disbelief (kufr) even though he is certain of the truth of the religion?

The treatment for obsessions is to combat them, ignore them, and seek refuge with Allah from Satan. So, whenever Satan instills obsessive thoughts regarding matters of faith, seek refuge with Allah from his evil and avoid dwelling on these obsessions. You will be rewarded for struggling against them, and these obsessions will not harm you as long as your heart is at peace with faith. If Satan whispers to you that you do not dislike these obsessions, then disregard his whisper. And if obsessive thoughts come to you regarding acts of worship, turn away from them and pay them no heed.