Do the Vedic Samhitas mention the Mahakavyas?

Question

The following are the 4 Mahakavyas, mentioned in the Upanishads, taking about the Advaita Philosophy:

1. Prajñānam Brahma (प्रज्ञानम् ब्रह्म) - "Insight is Brahman," or "Brahman is insight" - (Aitareya Upanishad 3.3 of the Rig Veda)
2. Ayam Ātmā Brahma (अयम् आत्मा ब्रह्म) - "This Self (Atman) is Brahman" - (Mandukya Upanishad 1.2 of the Atharva Veda)
3. Tat Tvam Asi (तत् त्वम् असि) - "That essence (tat, referring to sat, "the Existent") are you" - (Chandogya Upanishad 6.8.7 of the Sama Veda)
4. Aham Brahmāsmi (अहम् ब्रह्मास्मि) - "I am Brahman" - (Brihadaranyaka Upanishad 1.4.10 of the Yajur Veda)

In his book ‘Satyarth Prakash’, Swami Dayanand Saraswati says that Mahakavyas are a myth created by brahmins.

Therefore, my question is, do the Vedic Samhitas mention the Mahakavyas (and therefore the Advaita Philosophy)?

Kindly note: This is not a duplicate of What are the Mahakavyas?, which I have even linked above. I’m looking for their mention in Vedic Samhitas and not an explanation for what they are.

Answer 1

Vedas don't address Mahavakyas specifically. But they speak indirectly. They recognize Atman and Paramathma and speak that Purusha alone became all beings and knowing that Purusha bestows Moksha.

Hiraṇya-garbha is the golden germ which enters into creation after the first act of the creator. Hiraṇya-garbha has within itself the seeds of all things – the eternal archetype of Ideas – also known as nāma. Hiraṇya-garbha is the ‘great-self’, (mahān-ātma) which arises from the unmanifest —the avyakta. (Rig Veda 10.121.1)

Two Birds with fair wings, knit with bonds of friendship, in the same sheltering tree have found a refuge. One of the twain eats the sweet Fig-tree’s fruitage; the other eating not regardeth only.(Rig Veda I.164.20)

The tree whereon the fine Birds eat the sweetness, where they all rest and procreate their offspring, – Upon its top they say the fig is luscious; none gaineth it who knoweth not the Father.(Rig Veda I.164.22)

When the gods got the revelation of knowledge of Brahman they declared the teaching about That. That sage who knows the Supreme as described before will have sovereignty over Gods (for he has become the Inmost Self of all) (Vajansaneyi Samhita 31.21 of Yajurveda)

Purusha Nârâyana desired, 'Would that I overpassed all beings! would that I alone were everything here (this universe)!' He beheld this five-days’ sacrificial performance, the Purushamedha, and took it , and performed offering therewith; and having performed offering therewith, he overpassed all beings, and became everything here. And, verily, he who, knowing this, performs the Purushamedha, or who even knows this, overpasses all beings, and becomes everything here.(Shadpatha Brahmana 13:6:1:1)

No fear of death for the knower of the Atman. (Artharva Veda 10.8.44)

Answer 2

Vedas and vedic samhitas mention mahakavyas asas Itihaas and Purana.

As clouds of smoke proceed by themselves out of a lighted fire kindled with damp fuel, thus, verily, O Maitreyî, has been breathed forth from this great Being what we have as Rig-veda, Yagur-veda, Sama-veda, Atharvâṅgirasas, Itihâsa (legends), Purâna (cosmogonies), Vidyâ (knowledge), the Upanishads, Slokas (verses), Sûtras (prose rules), Anuvyâkhyânas (glosses), Vyâkhyânas (commentaries). From him alone all these were breathed forth. - "Brihadarankya Upanishad 2:4:10.

Nârada said: 'I know the Rig-veda, Sir, the Yagur-veda, the Sâma-veda, as the fourth the Âtharvana, as the fifth the Itihâsa-purâna (the Bhârata); the Veda of the Vedas (grammar); the Pitrya (the rules for the sacrifices for the ancestors); the Râsi (the science of numbers); the Daiva (the science of portents); the Nidhi (the science of time); the Vâkovâkya (logic); the Ekâyana (ethics); the Deva-vidyâ (etymology); the Brahma-vidyâ (pronunciation, sikshâ, ceremonial, kalpa, prosody, khandas); the Bhûta-vidyâ (the science of demons); the Kshatra-vidyâ - Chandoyoga Upanishad 7:1:2.

"In this way all the Vedas are manifested along with the kalpas,rahasyas, Brahmanas, Upanishads, Itihas, anvakhyatas and the puranas." - Gopatha Brahman purva 2:10.

Atharvaveda 11:7:24. Verses, and Songs, and magic hymns, Purāna, sacrificial text. All the celestial Gods whose home is heaven sprang from the Residue