ūrdhvamūlo'vākśākha eṣo'śvatthaḥ sanātanaḥ | tadeva śukraṃ tadbrahma tadevāmṛtamucyate | tasmiṃllokāḥ śritāḥ sarve tadu nātyeti kaścana | etadvaitat || 1 ||
Root up and branches down is this ancient asvattha tree, that (its source) is pure. That is Brahman and that alone is called immortal. On that, do all worlds depend and none passes beyond that. This verily is that.(Katha Upanishad 2.3.1)
That which is the root of this tree of Samsâra is indeed pure, bright, i.e., resplendent, the intelligence of âtman; that indeed is Brahman, being greater than all; that indeed is described as immortal in nature, being true; any other than that is a mere matter of speech, modification, name and falsehood and therefore subject to death. Commentary by adi Shankara.
Another translation
“This is that eternal Ashvattha Tree with roots above and branches below. That indeed is the pure. That is Brahman. That alone is the immortal.
[by SWAMI Krishnan Anda]
This verses clearly say only Brahman is immortal(or called immortal).
And commentary makes it even more clear, it only Brahman is immortal rest is subjected to death.
But it contradicts this verse :
When mortal man presents to thee Immortal God, Agni, his fuel or his sacrificial gift, Then thou art his Adhvaryu, Hotar, messenger, callest the Gods and orderest the sacrifice. (Rig Veda Verse 10.91.11)
This entire answer tells us that devatās are immortal.
Not just that it also contradicts the eternality of soul :
BG 2.20: The soul is neither born, nor does it ever die; nor having once existed, does it ever cease to be. The soul is without birth, eternal, immortal, and ageless. It is not destroyed when the body is destroyed.
MY QUESTION : The verse from Katha Upanishad is saying that only Brahman is immortal, but the verse I have presented also say that devatās are immortal and soul is immortal. The immortality of the devatās contradicts the verse
from Katha Upanishad(2.3.1).
What is the explanation for this contradiction.
One can say that the verse from Katha Upanishad is saying that Brahman is called immortal but still in many verses Agni is called immortal.