The Meaning of the Hadith: “Every deed of the son of Adam is for him except fasting” and the reason for the specific designation of fasting

Question:
Also among the questions that came to the program, Honorable Shaykh, he says: The hadith was reported. Why was fasting singled out? And I hope you will shed light on this hadith?

Answer:
Yes, this is a great hadith. Allah the Exalted says in the Qudsi hadith: Fasting. Allah the Exalted says: Fasting is for Me, and I will reward it. And the meaning of this, and Allah knows best, is that the reward for fasting is not limited to a number of multipliers.
Because the secret in this, or the wisdom in this, is that Allah said: Fasting is for Me, and I will reward it. He left his desire, his food, and his drink for My sake. And the bad breath of the fasting person, the bad breath of the fasting person is more pleasant to Allah than the scent of musk.
So this is a great hadith. And His saying “Fasting is for Me,” even though all deeds are for Allah, Glorified and Exalted is He, why was fasting singled out? Fasting was singled out because fasting differs from other deeds, because other deeds are seen and witnessed when the Muslim performs them: the one who prays, the one who gives charity, and other deeds that people witness.
As for fasting, it is an inner intention that no one knows except Allah, Glorified and Exalted is He, and people do not have access to it. Therefore, nothing distinguishes the fasting person from the one who breaks the fast except the intention; it is the intention that distinguishes between them. The fasting person does not know of his deed except Allah, Glorified and Exalted is He, and He is aware of it. Yes.