What is the ruling of Islamic law regarding one who sexually desires his daughter or fondles her without intercourse, and what is the degree of the sacredness of this act? What is the solution for ridding oneself of the whispers of Satan, and is it normal for fathers to desire their daughters?

Whoever allows himself to entertain sexual desire for his daughter or to lie with her, even playfully, has violated both divine law and natural inclination and has committed a grave matter. This is because a mahram is required to protect her honor, not to violate it. Whoever commits this forbidden act must offer sincere repentance to Allah, conceal his deed, and not publicize it. The effective remedy for such whisperings is to strengthen one's faith by seeking refuge in Allah Almighty, frequently supplicating, reciting the Quran, contemplating the verses of creed, accompanying the righteous, attending gatherings of knowledge, and drawing closer to Allah through good deeds.