Manava Dharmashastra 2.157

2.157

iyamadhyayanādhyetṛstutiḥ | kāṣṭhamayaḥ dāruṇā yaḥ kriyate krakacādinā hastyākṛtiḥ, sa yathā niṣphalaḥ, na hastikāryaṃ rājñāṃ śatruvadhādi karoti | evaṃ yo brāhmaṇo nādhīte sa kāṣṭhatulyaḥ, na kacidadhikārī| carmamayo mṛgaḥ carmavikāro'nyo'pi yo mṛgaḥ sa niṣphalo nā''kheṭakādikāryaṃ karoti | traya ete nāma mātraṃ bibhrati, na tasyārtham |

As the elephant made of wood, as the deer made of leather, so the non-learning Brāhmaṇa,—these three merely bear their names.—(157)

Medhātithi’s commentary (manubhāṣya):
This verse praises learning and the learner.

‘Made of wood’;—the form of the elephant made of wood by means of the said and other implements; just as this is useless, does not serve any useful purpose for the king, in the shape of killing his enemies and so forth,—so the Brāhmaṇa who does not learn is like a piece of wood, not fit for anything.

‘The deer made of leather’;—similarly the deer that has been made out of leather is useless; it is of no use for purposes of limiting, etc.

‘These three only bear their names’—and do not fulfil what is signified by these names.—(157)

‘Kāṣṭhamayo hasti’—“Probably allusions to old stories. Cf. the Bṛhatkathā for the ‘wooden elephant’... In Mahābhārata the same idea is expressed in slightly different words (12. 30. 40 ff.) and with added similes.” (Burnell-Hopkins).

Comparative notes by various authors
Baudhāyana, 1.1-11,
Parāśara, 8-16,
Vaśiṣṭha, 3.12,
—Reproduce the words of Manu.

Mahāhhārata, 12.3.6-46.—(Same as Manu, but reading ‘bibhrati’ for ‘dhāraka.’)