Manava Dharmashastra 4.12

4.12

tryahaihikāśvastanavṛttidārthyai prasaṃkhyānamidamāha | santoṣa āśrayitavyaḥ, na bahūnāmupajīvyaḥ syāmiti yācñākleśa āstheyaḥ | sukhārthī saṃyato bhavet | ‘saṃyamaḥ’ yātrikācchānādadhike nābhilāṣaḥ | santoṣo manasvināṃ sukhamūlam | duḥkhasya mūlaṃ viparyayaḥ asantoṣaḥ | mahadviduṣāṃ dainyaṃ, abhilaṣite vastunyasampattiḥ | tasmātsantoṣamāśrayet |

He who wants happiness should adopt perfect contentment and remain self-controlled. Happiness has its root in contentment, and its opposite is the root of unhappiness.—(12)

Medhātithi’s commentary (manubhāṣya):
With a view to laying stress upon the importance of the two means of living—‘to collect grains for three days’ and ‘not to possess grains enough for the morrow,’—the author adds this verse by way of reflection.

One should have recourse to contentment; that is, one should not make an effort to go about begging on a large scale, with a view to becoming dependent upon several persons.

‘He who wants happiness should remain self-controlled.’—‘Self-control’ consists in not wanting more wealth than what would suffice for bare subsistence.

‘Contentment’ is the root of happiness for all high-minded persons; and its opposite—i.e., Discontent—is the root of unhappiness; the non-accomplishment of what is desired being a source of great humiliation for the learned. For these reasons, one should have recourse to contentment.—(12)

This verse is quoted in Aparārka (p. 170), which remarks that in connection with all these ‘vratas’, it has to be borne in mind that what is exactly meant by the term ‘vrata’ is the mental determination that ‘I shall do this—I shall not do that’,—and that all these have to be taken up immediately after the Final Bath.

Comparative notes by various authors
Yājñavalkya (1.129).—‘He shall ever remain contented.’