Rif Gittin 20a {37b; 40b; 37b}

20a

{Gittin 37b}
Mishna:

עבד שנשבה ופדאוהו לשום עבד ישתעבד לשם בן חורין לא ישתעבד
רשב"ג אומר בין כך ובין כך ישתעבד:

SHOULD A [NON-JEWISH] SLAVE [OF A JEW] BE CARRIED OFF BY ROBBERS AND RANSOMED [BY A THIRD PARTY], IF [HE IS RANSOMED] AS A SLAVE HE GOES BACK TO SLAVERY, BUT IF [HE IS RANSOMED] AS A FREE MAN HE DOES NOT GO BACK TO SLAVERY.
RABBAN SHIMON BEN GAMLIEL SAYS: IN EITHER CASE HE GOES BACK TO SLAVERY.

{Gittin 40b}

עבד שעשאו רבו אפותיקי לאחרים ושיחררו שורת הדין אין העבד חייב כלום אלא מפני תיקון העולם כופין את רבו ועושה אותו בן חורין וכותב שטר חוב על דמיו
רשב"ג אומר אינו כותב אלא המשחרר

IF A MAN MAKES HIS SLAVE SECURITY [FOR A DEBT] TO ANOTHER MAN AND HE EMANCIPATES HIM, IN STRICT JUSTICE THE SLAVE IS NOT LIABLE FOR ANYTHING, BUT FOR THE BETTER ORDERING OF THE WORLD, HIS MASTER IS COMPELLED TO EMANCIPATE HIM, AND HE GIVES A BOND FOR HIS PURCHASE PRICE.
RABBAN SHIMON BEN GAMLIEL SAYS: HE DOES NOT GIVE A BOND BUT HE THAT EMANCIPATES HIM. {Rif has המשחרר, while the Mishna in our gemara has משחרר, which might translate as "but he emancipates him." To be explained in the gemara.}

{Gittin 37b}
Gemara:

במאי עסקינן אילימא לפני יאוש לשם בן חורין אמאי לא ישתעבד
ואלא לאחר יאוש לשם עבד אמאי ישתעבד
אמר רבא לעולם לאחר יאוש לשם עבד ישתעבד לרבו שני לשם בן חורין לא ישתעבד לא לרבו ראשון ולא לרבו שני
לרבו שני לא דהא לשם בן חורין פרקיה לרבו ראשון לא דהא לאחר יאוש הוה
רבן שמעון בן גמליאל אומר בין לשם עבד בין לשם בן חורין ישתעבד (בין לפני יאוש בין לאחר יאוש ישתעבד לשם עבד ישתעבד לרבו שני לשם בן חורין ישתעבד) לרבו ראשון כדחזקיה
דאמר מפני מה אמרו בין כך ובין כך ישתעבד שלא יהא כל אחד ואחד הולך ומפיל עצמו לגייסות ומפקיע עצמו מיד רבו

וחזינן לגאון דקא פסק הילכתא כרבנן דקי"ל יחיד ורבים הלכה כרבים

With what are we dealing {in the case of the captured slave}? If you say it is before {the owner} giving up, even if he were redeemed to be a free man, why should he not return to slavery?
And if it is rather after giving up, then even if he was redeemed to be a slave, why should he return to slavery?
Rava said: In truth, it was after giving up hope, but if {he was redeemed} to be a slave, he is a slave to his second master {, who redeemed him, but not the first}, while if {he was redeemed} to be a free man, he is not a slave to his first master nor to his second master. Not to his second master, for he redeemed him to be a free man. Not to his first master, for this was after he {=that master} gave up hope.
Rabban Shimon ben Gamliel says: Whether {he was redeemed} redeemed to be a slave or whether to be a free man, he becomes a slave (whether before giving up hope or after giving up hope, he becomes a slave. If {he was redeemed} to be a slave, he becomes a slave to his second master. If {he was redeemed} to be a free man, he becomes a slave) to his first master, in accordance with Chizkiyah,

{If we eliminate the text in parentheses, we have instead:
Rabban Shimon ben Gamliel says: Whether {he was redeemed} redeemed to be a slave or whether to be a free man, he becomes a slave to his first master, in accordance with Chizkiyah}

who said: Why was it said that in either case he becomes a slave? So that it should not be that every single one goes and casts himself to the robber bands, and thus take himself out from the hands of his master.

And we have seen that the Gaon ruled that the halacha is like the Sages, for we establish that in case of dispute between an individual and the many, the halacha is like the many.