Baudhayanadharmasutra 4.4

We will explain the (secret) penances which are not prescribed (by others, but by the offender himself, and) particularly what shall be done in (case) faults (have been committed) by men who, with concentrated minds, (are) intent (on the performance of their duties).

He who, standing in water, thrice recites that (hymn of) Aghamarshana (which begins), 'Both right and truth,' will be freed from all guilt.

He who, standing in water, thrice recites the verse, 'This spotted bull,' &c., will be freed from all guilt;

He who, standing in water, thrice recites the verse, 'Freed from the post as it were,' will be freed from all guilt.

He who, standing in water, thrice recites the verse, 'A swan dwelling in purity,' will be freed from all guilt;

Or, he who, standing in water, thrice recites the Sâvitrî, foot by foot, half verse by half verse, and afterwards entire, will be freed from all guilt;

Or, he who, standing in water, thrice recites the Vyâhritis, both separately and altogether, will be freed from all guilt;

Or, he who, standing in water, thrice recites the syllable Om alone, will be freed from all guilt.

Let him not teach these Institutes of the Sacred Law to one who is neither his son nor his pupil, nor has resided (in his house) less than a year.

The fee (for teaching it) is one thousand (panas, or) ten cows and a bull, or the worship of the teacher.