The reason for the revelation of the verse “the one who does not rule by what Allaah revealed…”, and that it refers to kufr in action not in belief.
2552- Indeed Allaah revealed, “the one who does not rule by what Allaah revealed then they are kaafir”, “they are dhaalim”, “they are faasiq”. Ibn Abbaas said, “Allaah revealed them with regards to two groups from the Jews one of which had overpowered the other to the point that they consented to and agreed that for every person that the victorious tribe (al-Azeeza) killed from the subjugated tribe (adh-Dhaleelah) then the ransom was 50 wasq (a unit of weight), and that for every person the subjugated tribe killed from the victorious then the ransom was 100 wasq, and they remained in this state until the Prophet (sallallaahu `alaihi wasallam) arrived in Madeenah and then both the tribes were subjugated, and that day they did not overcome him because of the peace treaty . Then the subjugated tribe killed a person from the victorious tribe and the victorious tribe sent someone demanding 100 wasq. So the subjugated tribe said: ‘can this ever be that two people have the same religion, same genealogy, same city and the ransom for some of them be half of the others? We only used to give you this ransom due to your injustice to us, and now that Muhammad has come we will not give you this.’ So a war almost started between them and then they agreed to make the Messenger of Allaah (sallallaahu `alaihi wasallam) judge between them. Then the victorious tribe said: ‘by Allaah, Muhammad will not give you twice the sum of what we gave them for they (the subjugated tribe) spoke the truth, they did not give us this ransom except as an injustice on our part and due to our power over them. So secretly send someone to Muhammad who can inform you of his opinion, if he gives you what you wish then agree to have him arbitrate, and if he does not then beware and do not agree to have him arbitrate.’ So they sent some people from the hypocrites to Muhammad. So when the Messenger of Allaah (sallallaahu `alaihi wasallam) came, Allaah informed him of all of their affair and what they desired and He, Azza wa Jall, revealed, “O Messenger! Let not those who hurry into disbelief grieve you, of such who say: ‘we believe’…” to His saying, “then they are faasiq” [5:41-47].” Then he (ibn Abbaas) said, “By Allaah they were revealed with regards to these two (Jewish tribes), and it was these two that Allaah, Azza wa Jall meant (in these verses)”
Related by Ahmad (1/246), at-Tabaraanee in ‘al-Mu’jam al-Kabeer’ (3/95/1) via the route of Abd ar- Rahmaan bin Abee az-Zinaad from his father from Ubaid Allaah bin Abd Allaah bin Utbah ibn Mas’ud from Ibn Abbaas that he said: and mentioned the hadeeth.
And in ‘ad-Durar al-Manthoor’ (2/281), as-Suyutee ascribed the hadeeth to Abu Dawood, ibn Jareer, ibn al-Mundhir, Abu ash-Shaykh, ibn Mardawiyyah from ibn Abbaas. And it is in the tafseer of ibn Jareer (10/352) in this form but he does not mention ibn Abbaas in his isnaad.
And in Abu Dawood (3576) is the (hadeeth relating to the) revelation of the three verses specifically for the Jews of Qareedha and an-Nadeer, contravening what may be understood from the saying of ibn Katheer in his tafseer (6/160) after reporting this long narration from Ahmad, “and Abu Dawood reports something similar from the hadeeth of ibn Abee az-Zinaad from his father.”
And the author of “ar-Rawd al-Baasim fee adh-Dhabb an as-Sunnah Abee al-Qaasim” quotes from him (ibn Katheer) that he declared the isnaad hasan. And I have not seen this in his book ‘at-Tafseer’ so maybe this occurs in his other works.
And declaring this hadeeth hasan is what the principles of this noble science dictate for it revolves around Abd ar-Rahmaan bin Abee az-Zinaad and he is as al-Haafidh (ibn Hajr) said, “truthful, his memorisation changed/failed when he moved to Baghdaad, and he was a faqeeh”
And the saying of al-Haythamee (8/16), “and the likes of it is reported by Ahmad and at-Tabaraanee, and in it is Abd ar-Rahmaan bin Abee az-Zinaad and he is da’eef, and he has been declared trustworthy, and the remaining narrators of Ahmad are trustworthy”.
I say: his saying “da’eef, and he has been declared trustworthy” is not good, because has determined the opinion that he is da’eef to be stronger than the opinion that he is trustworthy. And the truth is that he is in the middle and that he is hasan in hadeeth except when he contradicts (others), and this cannot be derived from his aforementioned saying. And Allaah knows best.
An important benefit:
Concerning Those Who Do Not Rule by what Allaah SWT has Revealed 
