I think that vv 7-8 in their entirety are interpolated, including the phrase "but on the contrary, when they saw that I had been entrusted with the good-news to the uncircumcised.." which more or less duplicates the the words "and when they percived the grace that was given to me" in verse 9.Ben C. Smith wrote:In verses 7-8 I have Peter, because I am not aware of any variants for these two instances. But I also take the part highlighted in yellow as an interpolation; this has been suggested before for many reasons, not least the weirdness of Paul switching back and forth between Cephas and Peter as names for the same man for no particular reason. The very lack of manuscript variations for the name of Peter in these two verses may point to this part having been added later than the other verses about Peter/Cephas, all of which contain such variants; the interpolation simply postdates the textual wars which produced those variants.
When these verses are omitted the text makes complete logical and grammatical sense:
In verse 9 it’s the “men of repute” who dole out the two missionary roles: the gentiles are given to Paul and Barnabas, and the Jews to James, Cephas and John. Cephas comes after James, and might therefore be considered marginally lower in rank. Verses 7-8 subtly alter this:6 And from those who were renowned to be something – what they were makes no difference to me; God shows no partiality – those, I say, who were of renown proposed no additions to me, 9 and when they perceived the grace that was given to me, then James, Cephas and John, who were renowned as pillars, extended the right hand of fellowship to me and Barnabas, so that we [should go] to the Gentiles and they [would go] to the circumcised; 10 only that we should remember the poor, which very thing I was diligent in doing.
These verses repeat the split in the missionary work but here turn it into a two-man show: moreover it isn't just the "men of repute" who delegate these roles - the wording now suggests that God himself has entrusted the Gentile mission to Paul, and the Jewish mission to Peter. It notably leaves James out of this divine election - which may be the precise point of the interpolation. This later interpolator has automatically adopted Peter’s Greek name, which was the name he had come to be famous by, rather than the Aramaic Cephas of the original text.7 but on the contrary, when they saw that I had been entrusted with the good-news to the uncircumcised, just as Peter had been entrusted with the good-news to the circumcised 8 for he who worked through Peter for the mission to the circumcised worked through me also for the Gentiles,