Garudapurana 1.122

The Glorious Garuḍa Mahāpurāṇa — 122
Brahmā said:
I shall tell you the supreme religious observance called the month-long fast.
A forest-dweller, an ascetic, or a woman should perform the month-long fast.

Having fasted on the eleventh day in the bright fortnight of the month of Āśvina,
one should undertake this religious observance for thirty days.

[Saying:] “From today onward, O Viṣṇu, until your awakening,
I shall worship you, fasting, for thirty days.

Between the bright twelfth days of Āśvina and Kārtika, O Viṣṇu,
if I should die in the interim, may my religious observance not be broken.”

Bathing at the three junctures of the day, the practitioner of the religious observance should worship Hari with perfumes and other offerings.
In the temple of the deity, one should forgo anointing the body with oil or perfume.

Then, having worshipped on the twelfth day, one should provide food to the twice-born.
Thereupon, one who performs Hari’s month-long fast should break the fast.

If the practitioner of the religious observance faints in the interim, one may consume milk and the like;
by milk and such, the religious observance is not destroyed, and one obtains enjoyment and liberation.

Thus ends the one hundred and twenty-second chapter, entitled “The Religious Observance of the Month-Long Fast,” in the section on conduct, within the first portion of the first section in the glorious and great Garuḍa Purāṇa.