(On my request, uncle expressed his thoughts on Ehd-e-Alast)
There are many pledges/oaths Qur'an talks about like the pledge taken by Bani Israel or the one taken by all the prophets and also the oath taken from the last prophet and we know of some pledges on the earth like the one the Muslims took under that tree outside Makkah (Hudaibiya).
There is one called ehd-e-Azal, as it is described in Qur'an in surah Al-A'raaf (VII) aya # 172. "And (remember) when your Lord brought forth from the children of Adam, from their loins, their seed (or from Adam's loin his offspring) and made them testify as to themselves (saying) 'am I not your Lord?, they said 'Yes we testify', lest you should say on the day of resurrection, 'verily we are not aware of it' " (I have used translation of Dr Muhsen rather than Yusuf Ali or others because he uses the word seed ). Also known in Urdu as "ehd-e-alast" taken from "alast-o-beRabbikum".
It is said that it is not just 'allegorical' description but an actual event that occurred after Allah SWT decided to send Adam AS to the earth. Some Ahadeeth say as soon as he descended on earth (in the Arafaat grounds). Descriptions of hadeethes given in various books of tafseer indicate how everybody understood n his/her own way the "taking out of all the persons to be born up-till the "Qiyamah" (how it happened). Clearly this was as good a miracle as the of birth of Adam AS or that of Amman Hawwa (Eve) and so there is no reason to reject that as a possibility but only accepting it as it is, rather than trying to derive some explanation from hadeeth descriptions. I see that many sahaba say this is how the prophet SAWS told us. Yet, the truth is best known to Allah SWT. The prophet himself could only talk in the terms that Sahaba could understand. We as His creation should just accept it as he wants us to. I do not wish to quote ahadeeth or what I understand from tafseers but just for example I shall give my understanding.
Tafheem-ul-Quran says the whole progeny of Adam AS was created out of Adam's Pusht (Sulb in Arabic) and not just the roohs (meaning rooh plus bodies). Then explanations need where on earth such a large collection of human beings could be placed. Some others say they were extremely small in body like ants (yes I read this in tafseer). Meaning that they did not require a large ground. Ibn-e- Kaseer says- what I understand- they were 'roohs' who were brought out and questioned and then put back (into the "Sulb") and this may seem more plausible than tafheem explanation. But really we dont have to think out in such terms as to how and where it happened.
As physicians/scientists (and this is purely my own idea, not meant for discussion) we may postulate possibility of 'gametes' (the seed) from which whole human body develops could have been miraculously brought out and placed back and of course Allah SWT can give the same understanding and ability to talk/say as the pledge to anything. But as I said before it is much easier to accept this miracle as it says in Qur'an than rely on any hadeeth (Not denying ahadeeth or the authority of it or that of prophet SAWS - Far it be from me to even think about it). If you will recall Allah SWT warned people not to question unnecessary things while Quran is being revealed (S. V, Aya 104 and 105) because it may turn your faith away. That is a very important aya/warning for us to stay away from going into explanations of things that are unnecessary. All we need to do is believe in that Ehd.
You also know some people from Sahaba (Ali RA for example) said they remember that pledge very clearly in their memory. Also that pledge forms the basis of the frequently quoted hadeeth that "every child is born a Muslim but the parents make him/her Christian or Jew or Majoosi" And this I am saying from Tafseer, not just my idea.
May Allah forgive me for my mistakes and misunderstanding and/or mis-interpretations.