Permissibility of fasting the 13th, 14th and 15th, Mondays and Thursdays of lunar months
Observing Sawm on Monday and Thursday is permissible. It is
on the authority of
Usamah ibn Zayd (may Allah be pleased with both of them) that the Prophet (peace be upon him) replied to the question of why he always observed Sawm on Monday and Thursday saying:
The works of the people are presented (to Allah) on Monday and Thursday.
In another narration:
I would like my deeds to be shown (to Allah) while I am fasting.
This Hadith clearly indicates that observing Sawm on Monday and Thursday is permissible and is a Sunnah (supererogatory act of worship following the example of the Prophet). Moreover, observing Sawm for three days of every month is also a Sunnah as stated in the Hadith authentically reported from the Prophet (peace be upon him).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.