'Abdullah bin 'Amr bin Al-'As (May Allah be pleased with them) reported: The Messenger of Allah (ﷺ) said, "Observing Saum (fasting) on three days of every month is equivalent to a full month's fasting."[Al-Bukhari and Muslim].

'Abdullah bin 'Amr bin Al-'As (May Allah be pleased with them) reported: The Messenger of Allah (ﷺ) said, "Observing Saum (fasting) on three days of every month is equivalent to a full month's fasting."[Al-Bukhari and Muslim].

وعن عبد الله بن عمرو بن العاص، رضي الله عنهما، قال‏:‏ قال رسول الله‏:‏ ‏ "‏صوم ثلاثة أيام من كل شهر صوم الدهر كله‏"‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏