This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahih Fazail-e-Amaal.
It is narrated from Sayyiduna Abu Imamah رضي الله عنه that the Prophet Muhammad صلی اللہ علیہ وآلہ وسلم said:
من صام يوما فى سبيل الله ، جعل الله بينه وبين النار خندقا كما بين السماء والأرض
"Whoever fasts for the sake of Allah, Allah creates a trench between him and the Hellfire as far as the distance between the heaven and the earth."
Reference: Sunan Tirmidhi, Book of Virtues of Jihad, Chapter on the Virtue of Fasting in the Way of Allah, Hadith No: 1624 - Al-Silsilah Al-Sahihah, No: 563.
عن أبى سعيد الخدري رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : ما من عبد يصوم يوما فى سبيل الله، إلا باعد الله، بذلك اليوم ، وجهه عن النار سبعين خريفا .
It is narrated from Sayyiduna Abu Saeed Khudri رضي الله عنه that the Messenger of Allah صلی اللہ علیہ وآلہ وسلم said: "Whoever fasts for one day in the way of Allah, Allah distances his face from the Hellfire by seventy years for that one day."
Reference: Sahih Bukhari, Book of Jihad and Expedition, Chapter on the Virtue of Fasting in the Way of Allah, Hadith No: 2840 - Sahih Muslim, Book of Fasting, Chapter on the Virtue of Fasting in the Way of Allah for those who can bear it, Hadith No: 1153.
Sayyiduna Abu Hurairah رضي الله عنه says the Messenger of Allah صلی اللہ علیہ وآلہ وسلم said:
كل عمل ابن آدم يضاعف الحسنة عشر أمثالها إلى سبعمائة ضعف ، قال الله عز وجل : إلا الصوم ، فإنه لي وأنا أجزي به ، يدع شهوته وطعامه من أجلي ، للصائم فرحتان، فرحة عند فطره، وفرحة عند لقاء ربه ، ولخلوف فيه أطيب عند الله من ريح المسك .
"Every deed of the son of Adam is multiplied, a good deed is from ten to seven hundred times. Allah the Exalted said: Except for fasting, it is for Me and I shall reward it. The fasting person leaves his desires and food for My sake. The fasting person has two joys: one at the time of breaking the fast and the other when he meets his Lord (he will be pleased). And the smell from the mouth of the fasting person is better to Allah than the scent of musk."
Reference: Sahih Muslim, Book of Fasting, Chapter on the Virtue of Fasting, Hadith No: 1151.
