Dear brother Hamzeh,
Wa alaikumus salaam,
Kindly see my humble thoughts below in response to your solicitation of an input.
"Do you think its between the People which goes back to the context in verse 5:42 those who came to the prophet for judgment ? That's what I understand it to be"
I do share such an understanding yes.
In such a context, for purposes of an admonition, the Prophet (pbuh) is given an option to 'turn away' (tu'ridhw) from them (Jews - al-ladhina hadu, 5:41) if he so wishes. If he otherwise opts to give a judgment (wa in hakamta), he is instructed to give a just one (bil qisthwi) which is however readily already to be found within the Taurat they possess in which are God's judgments - 'hukmu allahi' (5:43), guidance (hudan) and light (wa nurun) - 5:44.
Those from the Jews who do not judge according to what God revealed (bi ma an-zalallahu) of such judgments, guidance and light from the 'Taurat' as did their prophets (an-nabiyyuna), rabbis (ar-rabbaniyyuna) and scholars (al-ahbaru), they actually are the disbelievers (humu al-kafirun) - 5:44. Such instances of judgments/ laws (hukm) are outlined (5:45, life for a life...) and that those who do not rule according to such revealed judgments/ laws are the unjust (humu ad-dhwalimun).
In the footsteps of those previous prophets to the Children of Israel, Prophet Isa (pbuh) was sent with the 'Injeel' as a confirmation of the 'Taurat,' as a guidance (hudan), light (nurun) and counsel (maw'idhwatan) to the righteous (5:46) thus those who followed it were supposed to judge (walyahkum) according to what was revealed (bi ma an-zalallahu) of judgment in it (fihi) - 5:47.
Therefore, in light of this foregoing precept (5:43, 5:47), the Prophet (s.a.w) was supposed to judge the Jews and the Christians according to the Taurat and Gospel respectively, the Qur'an superseding them both altogether.
"What is your understanding of the part of the verse that says "and judge between them by what Allah(swt) has reaveled"? It is said once in 5:48 And once in 5:49"
'By what God has revealed' (bi ma an-zala llahu) in verses 5:48-49 in the context of judgment over People of the Book would still refer to 'what God has revealed' (bi ma an-zala llahu) for the Jews (5:44) as well as 'what God has revealed' (bi ma an-zala llahu) for the Christians (5:47).
To be sure of what was truly revealed in their scriptures (5:44, 5:47) which is what they are actually to be judged against, such that he would be judging between them justly (bil qisthwi) -5:42, the Prophet (s.a.w) is to check whatever is prescribed for them in the scripture they possess (e.g 3:93, 'say bring the Taurat...') against that which is approved of them in the Qur'an (16:118, 6:146). Therefore, the Qur'an stands as the ultimate check (muhaymin) against scriptures of the People of the Book as can again be seen in the verse 5:45 against Exodus 21:23-25 (also Leviticus 24:18-21 and Deuteronomy 19:21).
In such a way, the Prophet (s.a.w) would avoid pursuing their desires - 'ahwahum' (2:120) in the form of 'laws' (hukm) possibly some from their times of ignorance (5:50, hukma al-jahiliyyati) brought forth (yaktubuna al-kitaba bi aydihim) in the name of religion (2:79) or rather doctoring the scriptures (5:15, tukhfuna) through for instance, attempted obfuscation (5:41, yuharrafuna al-kalima min ba'di mawadhwi'ihi). If after checking their scriptures against the Qur'an the Prophet (s.a.w) encounters a disparity, then surely, that particular judgment/ rule is not part of their commandments/ judgments but from their own whims (ahwahum).
"And if so would you say that it is expected that Jews and Christians would also need to judge by what they were given by using the Quran as a criterion regarding their books and would judge in their countries who ever abides therein including Muslims?"
In my humble opinion, on the other hand, yes, I do resonate the sentiment that the same is to be reciprocated to believers of the Qur'an in a government (Jewish/ Christian) whose primary scripture of authority is that of the People of the Book; i.e, one that guides/ rules by the 'Taurat'/ 'Injeel'/ 'al-Kitab' in truth - the Qur'an being the final check (muhaymin) and criterion (furqan) sifting through in this case the main authoritative scripture ('al-Kitab'). However, collectively, together with those subjects that are exclusive followers of the Qur'an, such a Jewish/ Christian community is descriptively Muslim.
In summary therefore, the Prophet (s.a.w) and believers of the Qur'an were to use the Qur'an to discern that which 'has been revealed' by God (ma an-zalallahu) in the former scriptures when judging them lest they follow their desires hence their doctored creed (mil-lat). See the following quotation:
"And the Jews (al-yahuda) will not be pleased with thee, nor will the Christians (an-Naswara), till thou follow their creed (mil-latahum). Say: Lo! the guidance (huda) of Allah (Himself) is the Guidance (al-huda). And if thou shouldst follow their desires (ahwa-ahum) after the knowledge which hath come unto thee, then wouldst thou have from Allah no protecting guardian nor helper." [Qur'an, Al-Baqarah 2:120]
However, bearing in mind that each of nations (ummat) was sent a prophet with a given set code of rules (hukm) and devotional acts (mansakan), each is supposed to race in good works within their law (shir'atan) and avoid unnecessary disputes across such codes of conduct (minhajan).
Believers of the Qur'an should not falter in their 'creed,' 'law' nor 'way' for they are upon an 'upright guidance' (hudan mustaqim). Given the context, this was clearly an admonition for the Prophet (s.a.w). See the verse below:
"For every Ummah We have appointed acts of devotion (mansakan), which they observe. So do not let them dispute with you in this matter. And invite to your Lord; you are upon a upright guidance (hudan mustaqim)." [Qur'an, Al-Hajj 22:67]
Hopefully that clarifies my position. Thanks for giving me the chance to elucidate further.
Regards,
Athman.