Bramhana (like Aitareya brAhmana, satapata Bramhana, etc) are said to be part of Vedas and seem to expound the meaning of Samhita mantra and how to do Yajna. They also contain many legends like story of Yajnavalkya, Ajatshatru, Janaka etc.
On the other hand Veda are said to be timeless and not creation of any human.
So how can Bramhana be part of Veda/Shruti when they contain stories of real people?
In this aspect they seem similar to Smritis like Ramayan, Mahabharata etc.
The following is the answer provided by Sri Kiron Krishnan in another site, on the same subject.
Actually, if Vedas refer to the revealed, inspired visions of the
sages, then they comprise undoubtedly of only the poetic saṃhitās of
the kavis, also called Ṛṣis. The rest of the prose don’t have any
metrical constraint, they can vary to any limit, and are works
illustrating the use of these verses in some rituals, or speculations
related. Only the Ṛks, sāmans having chandases and Yajus formulas
comprise of the revealed vision. Rest are human constructs over it,
having little to do with the sages or their vision.
But, people. Their beliefs.
Pūrva mīmāṃsakas largely believe that Vedas were revealed only for the
purpose of yajñas because that is what is said by Brahmanas and Pūrva
mīmāṃsaka scriptures. Thus, the verses of Vedas cannot have any
independent existence other than the rituals to which they are
applied. And this also makes them consider both mantras and brāhmaṇas
Uttara mīmāṃsakas are clever, for they have already planned great
philosophies from easily accessible Upanishads and are too illiterate
or too impatient or too contemptuous to learn or even check Vedas and
Brahmanas, so they consider Upanishads as Vedas too, though many of
these Upanishads are not even composed in Vedic language, and have
nothing to do in content with Vedas.
Medieval Hindus tried to make Itihāsas or sometimes even Puranas as
fifth Veda too, for they loved stories and were so reluctant to even
spend some effort to study Vedas or what they are.
Then came Arya samaj. Dayanand considered only saṃhitās as Vedas, but
also honoured Manu smṛti, and believed in karma and rebirth, for
reasons only he knows.
Then come our great Hare Kṛṣṇas. For them, saṃhitās are already out of
syllabus. Instead, they have two Vedas - Bhagavad Gītā (as it is) and
Śrīmad Bhāgavatam. (translated by ISKCON) And they put up great sites
having “Vedas” “Vedic” in names, and you will see nothing but SB and
BG in them.
The idea about what Vedas are, among people, generally decreases in
the order :
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