Gita Chapter 17.16 to 17.20

Manahprasaadah saumyatwam maunamaatmavinigrahah;
Bhaavasamshuddhirityetat tapo maanasamuchyate.
16. Serenity of mind, good-heartedness, purity of nature, self-control—this is called mental austerity.

Shraddhayaa parayaa taptam tapastattrividham naraih;
Aphalaakaangkshibhiryuktaih saattwikam parichakshate.
17. This threefold austerity practised by steadfast men with the utmost faith, desiring no reward, they call Sattwic.

Satkaaramaanapoojaartham tapo dambhena chaiva yat;
Kriyate tadiha proktam raajasam chalamadhruvam.
18. The austerity which is practised with the object of gaining good reception, honour and worship and with hypocrisy, is here said to be Rajasic, unstable and transitory.

Moodhagraahenaatmano yat peedayaa kriyate tapah;
Parasyotsaadanaartham vaa tattaamasamudaahritam.
19. The austerity which is practised out of a foolish notion, with self-torture, or for the purpose of destroying another, is declared to be Tamasic.

Daatavyamiti yaddaanam deeyate’nupakaarine;
Deshe kaale cha paatre cha taddaanam saattwikam smritam.
20. That gift which is given to one who does nothing in return, knowing it to be a duty to give in a fit place and time to a worthy person, that gift is held to be Sattwic.

Gita Chapter 6.06 to 6.10

Bandhuraatmaa’tmanastasya yenaatmaivaatmanaa jitah;
Anaatmanastu shatrutwe vartetaatmaiva shatruvat.
6. The self is the friend of the self for him who has conquered himself by the Self, but to the unconquered self, this self stands in the position of an enemy like the (external) foe.

Jitaatmanah prashaantasya paramaatmaa samaahitah;
Sheetoshna sukha duhkheshu tathaa maanaapamaanayoh.
7. The Supreme Self of him who is self-controlled and peaceful is balanced in cold and heat, pleasure and pain, as also in honour and dishonour.

Jnaana vijnaana triptaatmaa kootastho vijitendriyah;
Yuktah ityuchyate yogee samaloshtaashmakaanchanah.
8. The Yogi who is satisfied with the knowledge and the wisdom (of the Self), who has conquered the senses, and to whom a clod of earth, a piece of stone and gold are the same, is said to be harmonised (that is, is said to have attained the state of Nirvikalpa Samadhi).

Suhrinmitraary udaaseena madhyastha dweshya bandhushu;
Saadhushwapi cha paapeshu samabuddhirvishishyate.
9. He who is of the same mind to the good-hearted, friends, enemies, the indifferent, the neutral, the hateful, the relatives, the righteous and the unrighteous, excels.

Yogee yunjeeta satatamaatmaanam rahasi sthitah;
Ekaakee yatachittaatmaa niraasheeraparigrahah.
10. Let the Yogi try constantly to keep the mind steady, remaining in solitude, alone, with the mind and the body controlled, and free from hope and greed.