Few thoughts here...
"sa ya eSo aNima aitadAtmyaM idaM sarvam tat satyam sa Atma tat tvam asi Svetaketu"
That (Sa) which (ya) those (eSa) minuteness/atomicity (aNima) those property of Atman (etad Atmya) here (idaM) everything (sarvam) is that eternity (tat satyam), that Atman (sa Atma) that (tat) in you (tvam) exists (asi) Svetaketu
"The property of Atman is that of minuteness which is present in everything as eternal, that Atma exists in you Svetaketu" - says Uddalaka.
aNima is difficult to be translated. it can be called 'minuteness', 'atomicity', 'mystic potency' etc etc etc. it is the property of Atma. It is present in everything as eternal. That potency/minuteness exists in you Svetaketu, says his father, in Chandogya Upanishad.
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Chandogya Upanishad also describes this property of Atma in more detail.
A. Tasya kva mulam syad anyatra adbhyah - That which is the 'root-cause' of others. (which is not caused by anything else)
B."..........yad-yad bhavanti,tadabhavanti" -- whichever manifests that unmanifests". - Causing continuous manifestation
C. "imah sarvah prajah sataagamya na viduh, sata agacchamaha iti" - that by which everything goes in and out of consciousness (sleep/wake up) (and remain the same)
D. "Na jivo mriyata" - Living beings die, but the 'life' itself does not die
E. "esho’nimna evammahan nyagrodhas-tishthati" - That which causes a small seed to grow into a banyan tree
F. Like a salt dissolved in water is not visible, but changes taste, that which is dissolved and hence inferred
G. That from which we have come a long way, blindfolded and to locate our origin receiving complex set of instructions
H. That which makes the 'manas', drives the 'prAna' and the energy metabolism (tejas)
So the property of Atman is the 'root-cause', causes repeated manifestation, gives consciousness, ensures life in itself does not die out, that causes a small seed to grow big, that which may not be seen, but inferred, from which we have come a long way blindfolded and hence need complex instructions to locate it, that which is in the manas.
Modern science may call it 'process of evolution'. But who drives the evolution..? So Chandogya Upanishad calls it the 'property of evolution' which is located everywhere and deep inside as the 'Atma'.
Vedantins call it the 'Soul'.
Philosopher call it the 'Consciousness'.
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The concept of surrender comes from 'nyAsa' mentioned in vedas and Upanishads. 'nyAsa' actually means 'giving up ownership', 'depositing/delivering', 'resigning', 'renunciation'. saMnyAsa means giving up everything.
The realisation that there is this 'Atma' or 'property of evolution' that changes everything, that is present everywhere leads us to 'nyAsa', a sense of giving up. We do not see us and others as 'originators' but beings caught in the torrent of evolution/Atma.
This leads to giving up of the sense of 'I am the powerful/cause' attitude. This the 'nyAsa' or giving up and understanding our actions in the overall scheme of evolution.
'nyAsa' is this realization, rather than an external submission.
-TBT