Sandilya is the 103rd of the 108 upanishads and is attached to the Atharva Veda. It is part of a set of scriptures called the Yoga Upanishads which deal mostly with ashtanga, or eight-limbed, yoga. This excerpt from chapter one is important for its listing of the ten yamas and ten niyamas. These restraints and observances constitute the first two of the eight limbs of classical yoga--establishing a foundation of good conduct and piety so that hatha yoga and meditation can be successful.
Om! O Devas, may we hear with our ears what is auspicious, may we see with our eyes what is auspicious, O ye worthy of worship! May we enjoy the term of life allotted by the Devas, praising them with our body and limbs steady! May the glorious Indra bless us! May the all-knowing Sun bless us! May Garuda, the thunderbolt for evil, bless us! May Brihaspati grant us well-being! Om! Let there be Peace in me! Let there be Peace in my environment! Let there be Peace in the forces that act on me!
Sage Sandilya questioned Atharvan thus: "Please tell me about the eight angas (parts or limbs) of yoga which are the means of attaining to Atman."
Atharvan replied: "The eight angas of yoga are yama, niyama, asana, pranayama, pratyahara, dharana, dhyana and samadhi. Of these, yama (restraints) is of ten kinds; and so is niyama (observances). There are eight asanas (yoga postures). Pranayama (breath control) is of three kinds; pratyahara (sense withdrawal) is of five kinds; so also is dharana (concentration). Dhyana (contemplation) is of two kinds and samadhi (Realization) is of one kind only.
"Under yama are ten: ahimsa, satya, asteya, brahmacharya, daya, arjava, kshama, dhriti, mitahara and saucha. Of these, ahimsa is the not causing of any pain to any living being at any time through the actions of one's mind, speech or body. Satya is the speaking of the truth that conduces to the well-being of creatures, through the actions of one's mind, speech, or body. Asteya is not coveting of another's property through the actions of one's mind, speech or body. Brahmacharya is the refraining from sexual intercourse in all places and in all states in mind, speech or body. Daya is kindliness towards all creatures in all places. Arjava is the preserving of equanimity of mind, speech or body in the performance (or non-performance) of the actions ordained (or forbidden) to be done. Kshama is the bearing patiently of all pleasant or unpleasant things, such as praise or physical aggression. Dhriti is the preserving of firmness of mind during the period of gain or loss of wealth or relatives. Mitahara is the taking of nutritious food, leaving one-fourth of the stomach empty. Saucha is of two kinds, external and internal. Of these, the external is the cleansing of the body by earth and water; the internal is the cleansing of the mind. This (i.e., internal cleansing) is to be attained by means of the Adhyatma-Vidya (Science of Self).
"Under niyama (religious observances), are ten: tapas, santosha, astikya, dana, ishvarapujana, siddhanta-shravana, hri, mati, japa and vrata. Of these, tapas is the emancipation of the body through observance of such penances as krichchhra, chandrayana (both are types of fasts), etc., according to rules. Santosha is being satisfied with whatever comes to us of its own accord. Astikya is the belief in the merits or demerits of actions as stated in the Vedas. Dana is the faithful giving to deserving persons of lawfully earned money, grains, etc. Ishvarapujana is the worshiping of Vishnu, Rudra, etc., with pure mind according to one's ability. Siddhanta-sravana is the inquiry into the significance of Vedanta. Hri is being ashamed if one's behavior violates the rules of the Vedas and of society. Mati is faith in the paths laid down by the Vedas. Japa is the practicing of the mantras into which one is duly initiated by his spiritual instructor and which is not against (the rules of) the Vedas. It is of two kinds--the spoken and the mental. The mental is associated with contemplation by the mind. The spoken is of two kinds--the loud and the low. The loud pronunciation gives the reward as stated in the Vedas, while the low one gives a reward thousand times that. The mental gives a reward ten millions times that. Vrata is the regular observance of (or refraining from) the actions enjoined (or prohibited) by the Vedas.
K. Narayanasvami Aiyar published this translation of Sandilya Upanishad (slightly edited here) in 1914 along with the Adyar Library as part of his book, Thirty Minor Upanishads. The translations had previously appeared in the monthly journal, The Theosophist. He collaborated in the work with Sundara Sastri.
The Vedas are the divinely revealed and most revered scriptures, shruti, of Hinduism, likened to the Torah (1,200 bce), Bible New Testament (100 ce), Koran (630 ce) or Zend Avesta (600 bce). Four in number, Rig, Yajur, Sama and Atharva, the Vedas include over 100,000 verses. Oldest portions may date back as far as 6,000 bce.