Every day of the week is dedicated to a particular god/goddess based on the Indian mythology. There is a sign of every day based on a mythological myth and a custom to worship that day. It is believed that worshipping Lord Vishnu, on Thursdays is a lucky charm for you. Worshipers of Lord Vishnu observe a fast on that day. It is not only Lord Vishnu, but all the incarnations of Lord Vishnu who are worshipped on Thursday.
The rituals followed on a Thursday:
Every Thursday, Pujas for Lord Vishnu are conducted. Lord Vishnu’s idol is showered with ghee and milk or panchamrut. The panchamrut is a mixture of five substances: Milk, ghee, curd, honey, and sugar. After the Puja, the panchamrut is often distributed as prasadam.
Those who observe fast also have meals which are rich in substances that go in the panchamrut. The fast allows meal only once. All the devotees often gather and read or exchange their knowledge on Srimad Bhagwad Gita. Srimad bhagwad Gita holds a lot of importance because; it is given by Lord Krishna, an incarnation of Lord Vishnu.
Thursday is also called as ‘Guruvaar’ or ‘Brihaspatiwar’. ‘Guruvaar’ indicates that the day is devoted to the teachers the ‘gurus’. It is a good custom to seek blessings from your teachers on Thursdays.
It is also dedicated to Brihaspati i.e. the Venus planet. Thursday has a special astrological significance. If the place of the planet in the venus in one’s starts is unfavorable for one’s fortune, people are advised to take some special care on Thursdays. It is advised to observe a fast, wear and donate yellow clothes, and offer the gods yellow colored flowers. The color yellow has a special significance.
The devotees on a vrat, ideally wear yellow clothing, consume yellow food and offer yellow flowers to Lord Vishnu. The food is consumed only once and the meal preferably includes chana dal i.e. Bengal gram with ghee.
There are several stories which explain the reason for observing fast (Upvaas), on a Thursday. Many stories are from the regional folklore and vary in every region. However, the central thought being that he who performs Puja and follows the customs of vrat (fast) shall be bestowed with prosperity and success.