Garudapurana 1.123

The Glorious Garuḍa Mahāpurāṇa — 123
Brahmā said:
I shall speak of the religious observances in the month of Kārtika: having bathed, one should worship Viṣṇu,
for a month by eating a single meal, by eating only at night, or by eating only unbegged food,

or with milk, vegetables, fruits, and the like, or again by fasting.
Freed from all sins, with desires fulfilled, one goes to Hari.

A religious observance for Hari is always excellent; then in the southern course of the sun,
then during the four-month period, and therefore in the month of Kārtika, the five-day observance of Bhīṣma.

Then one should perform that excellent religious observance on the eleventh day of the bright fortnight.
Having bathed at the three times of day, one should honor the ancestors and worship Hari with barley and other offerings.

Observing silence, one should worship with ghee and other substances, with pañcagavya, and with waters;
having bathed [the deity], one should then anoint him with camphor and similar unguents.

A twice-born should burn incense of bdellium smeared with ghee for five days.
Offering a food-offering of sweet milk-rice, he should recite [the mantra] one hundred and eight times.

“Oṃ, salutation to Vāsudeva.” With this eight-syllable mantra
ending in svāhā, he should offer oblations of ghee, rice, sesame, and other substances.

On the first day, he should worship Hari’s feet with lotuses; on the second, / the region of the knees with bilva leaves; and on the other [day], the navel with fragrant paste;

the shoulders with bilva and hibiscus flowers; and on the fifth day he should worship the head / with jasmine. He should sleep on the ground, and in sequence consume cow-dung,

cow-urine, yogurt, milk, and on the fifth day pañcagavya.
On the fifteenth day the practitioner of the religious observance should eat only at night; he attains enjoyment and liberation.

The religious observance of the eleventh day is perpetual; one should observe it in both fortnights.
It destroys the flood of sins and hell, bestows everything, and grants the world of Viṣṇu.

Where there is the eleventh day, the twelfth day, and at the end of night the thirteenth day,
where there is the perpetual eleventh day, there Hari is present.

Where the eleventh day is mixed with the tenth day, the asuras and others dwell there.
One should break the fast on the twelfth day; one should observe it [even] in impurity from birth or death.

One should fast on the fourteenth day and the first day when mixed with the preceding day;
O sage, the full moon day and the new moon day when mixed with the first day [are observed].

One should fast on the second day mixed with the third, and also the third day / always conjoined with the fourth; the fourth joined with this [fifth]; / the fifth combined with the sixth; and the seventh joined with the sixth.

Thus ends the one hundred and twenty-third chapter, entitled “The Religious Observances of the Five Days of Bhīṣma and Others,” in the section on conduct, within the first portion of the first section in the glorious and great Garuḍa Purāṇa.