The apparatus is from LaParola, but it seems to have skipped Sinaiticus and Vaticanus in one spot, and I have put them back, marked with a tilde (~).
1.
Galatians 1.18-19: 18 Then three years later I went up to Jerusalem to become acquainted with Cephas, and stayed with him fifteen days. 19 But I did not see any other of the apostles except James, the Lord’s brother.
1.18
Κηφᾶν] p46 p51 א* A B 33 424c 467 823 920 1739 1912 syrp syrh(mg) syrpal copsa copbo eth WH NR CEI Riv Nv NM
Πέτρον] אc D F G K L P Byz ς ND Dio TILC
1.18
Κηφᾶν] p46 p51 א* A B 33 424c 467 823 920 1739 1912 syrp syrh(mg) syrpal copsa copbo eth WH NR CEI Riv Nv NM
Πέτρον] אc D F G K L P Byz ς ND Dio TILC
I select Cephas here because (A) our earliest (p46) and often most reliable (א B) extant manuscripts have Cephas and (B) I cannot think of a good reason to have turned Peter into Cephas here.
Marcion may have lacked this entire section, verses 18-24, however, so the choice here may not matter so much.
2.
Galatians 2.1-10: 2 Then after an interval of fourteen years I went up again to Jerusalem with Barnabas, taking Titus along also. 2 It was because of a revelation that I went up; and I submitted to them the gospel which I preach among the Gentiles, but I did so in private to those who were of reputation, for fear that I might be running, or had run, in vain. 3 But not even Titus, who was with me, though he was a Greek, was compelled to be circumcised. 4 But it was because of the false brethren secretly brought in, who had sneaked in to spy out our liberty which we have in Christ Jesus, in order to bring us into bondage. 5 But we did not yield in subjection to them for even an hour, so that the truth of the gospel would remain with you. 6 But from those who were of high reputation (what they were makes no difference to me; God shows no partiality) — well, those who were of reputation contributed nothing to me. 7 But on the contrary, seeing that I had been entrusted with the gospel to the uncircumcised, just as Peter had been to the circumcised 8 (for He who effectually worked for Peter in his apostleship to the circumcised effectually worked for me also to the Gentiles), 9 and recognizing the grace that had been given to me, James and Cephas and John, who were reputed to be pillars, gave to me and Barnabas the right hand of fellowship, so that we might go to the Gentiles and they to the circumcised. 10 They only asked us to remember the poor — the very thing I also was eager to do.
2.9
Ἰάκωβος καὶ Κηφᾶς καὶ Ἰωάννης] ~א ~B Byz ς WH
Ἰάκωβος καὶ Πέτρος καὶ Ἰωάννης] p46 itr
Πέτρος καὶ Ἰάκωβος καὶ Ἰωάννης] D F G itd itg goth Marcion Origenlat Ambrosiaster Victorinus-Rome Ephraem Marius Mercator
2.9
Ἰάκωβος καὶ Κηφᾶς καὶ Ἰωάννης] ~א ~B Byz ς WH
Ἰάκωβος καὶ Πέτρος καὶ Ἰωάννης] p46 itr
Πέτρος καὶ Ἰάκωβος καὶ Ἰωάννης] D F G itd itg goth Marcion Origenlat Ambrosiaster Victorinus-Rome Ephraem Marius Mercator
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.
3.
Galatians 2.11-14: 11 But when Peter came to Antioch, I opposed him to his face, because he stood condemned. 12 For prior to the coming of certain men from James, he used to eat with the Gentiles; but when they came, he began to withdraw and hold himself aloof, fearing the party of the circumcision. 13 The rest of the Jews joined him in hypocrisy, with the result that even Barnabas was carried away by their hypocrisy. 14 But when I saw that they were not straightforward about the truth of the gospel, I said to Peter in the presence of all, "If you, being a Jew, live like the Gentiles and not like the Jews, how is it that you compel the Gentiles to live like Jews?"
2.11
Κηφᾶς] א A B C H P 33 103 104 181 263 424c 436 vg syrp syrh(mg) copsa copbo arm eth WH NR CEI Riv Nv NM
Πέτρος] D F G K L Byz syrh(text) goth Marcion Victorinus-Rome Chrysostom Marius Mercator ς ND Dio TILC
2.14
Κηφᾷ] p46 א A B C H 10 33 88 255 263 424c 467 1319 2127 vg syrp copsa copbo arm eth WH NR CEI Riv Nv NM
Πέτρῳ] D F G K L P Byz itd itg vgmss syrh goth ς ND Dio TILC
2.11
Κηφᾶς] א A B C H P 33 103 104 181 263 424c 436 vg syrp syrh(mg) copsa copbo arm eth WH NR CEI Riv Nv NM
Πέτρος] D F G K L Byz syrh(text) goth Marcion Victorinus-Rome Chrysostom Marius Mercator ς ND Dio TILC
2.14
Κηφᾷ] p46 א A B C H 10 33 88 255 263 424c 467 1319 2127 vg syrp copsa copbo arm eth WH NR CEI Riv Nv NM
Πέτρῳ] D F G K L P Byz itd itg vgmss syrh goth ς ND Dio TILC
These two instances have to go together in the text, for surely Paul is rebuking the same man he is opposing in Antioch. But here is where I am differing from the usual textual reconstructions in selecting Peter instead of Cephas. My reason is simply that Cephas seems to be the Alexandrian (א B) or Egyptian (p46) favorite for these verses, and we can be fairly certain that a debate over Cephas and Peter in this very context took place in Alexandria:
Eusebius, History of the Church 1.12.2: 2 Ἡ δ´ ἱστορία παρὰ Κλήμεντι κατὰ τὴν πέμπτην τῶν Ὑποτυπώσεων· ἐν ᾗ καὶ Κηφᾶν, περὶ οὗ φησιν ὁ Παῦλος· « Ὅτε δὲ ἦλθεν Κηφᾶς εἰς Ἀντιόχειαν, κατὰ πρόσωπον αὐτῷ ἀντέστην», ἕνα φησὶ γεγονέναι τῶν ἑβδομήκοντα μαθητῶν, ὁμώνυμον Πέτρῳ τυγχάνοντα τῷ ἀποστόλῳ. / 2 This is the account of Clement in the fifth book of his Hypotyposes, in which he also says that Cephas was one of the seventy disciples, the one concerning whom Paul says, "When Cephas came to Antioch I withstood him to his face," a man who bore the same name as the apostle Peter.
This is Clement of Alexandria, of course. So the situation in 2.11, 14 is very much unlike the situation in 1.18, since here there is a clear and obvious reason why Peter might have been changed to Cephas: to spare him the wrath of the apostle Paul and pawn it off on the seemingly less important Cephas.
If this reconstruction is correct, then Paul went to visit Cephas (1.18, assuming for the sake of argument that this is part of the original text) in Jerusalem, and then went again to visit the three pillars: James, Cephas, and John. Later, however, in Antioch, he had a run-in with a different person, named Peter. If 1.18 is original, then both Cephas and Peter are known enough to the Galatians (at least) that they do not require a special introduction beyond their name alone (1.18; 2.11); if 1.18 is not, then Cephas is not necessarily that well known, as he is given a more proper introduction as one of the "pillars" in 2.9.
Again, I have no absolute commitment to this scenario; just throwing it out there, as it occurred to me recently and differs from the usual textual reconstructions. What do you think?
Ben.
ETA: Parking this here for future reference:
Bezalel Porten, Elephantine Papyri in English B42, lines 10-12, page 236 (Aramaic from Craig A. Evans, “A Fishing Boat, a House, and an Ossuary,” in The Missions of James, Peter, and Paul, page 220):
10 The witnesses herein: Attarmalki son of Kilkilan; Sinkishir son of Shabbethai; Saharakab son of Cepha [בר כפא];
11 Nabushillen son of Bethelrai; Eshemram son of Eshemshezib; Varyazata son of Bethelzabad;
12 Heremnathan son of Paho; Eshemzabad son of Shawyan.
10 The witnesses herein: Attarmalki son of Kilkilan; Sinkishir son of Shabbethai; Saharakab son of Cepha [בר כפא];
11 Nabushillen son of Bethelrai; Eshemram son of Eshemshezib; Varyazata son of Bethelzabad;
12 Heremnathan son of Paho; Eshemzabad son of Shawyan.
The papyrus in question is dated to around 416 BC. It is also known as BMAP #8, from the Brooklyn Museum Aramaic Papyri.