Abu Sa'id Al-Khudri (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "Every slave of Allah who observes Saum (fasting) for a day in the Cause of Allah, Allah will keep his face from Hell-fire at a distance of seventy years."[Al- Bukhari and Muslim]. (AR)
App reference (AR): Book 12, Hadith 55 (AR)
Arabic/English book reference (AR): Book 12, Hadith 1339 (AR)