The Mishna on today’s daf teaches a number of situations in which Rabban Gamliel did not personally follow the laws that he taught. For example, although a groom is not obligated in the recitation of the Shema, on his wedding day Rabban Gamliel did recite it, explaining to his students that he was unable to refrain from the acceptance of the yoke of the Kingdom of Heaven even for one moment.
The Mishna continues:
And when his slave, Tavi, died, Rabban Gamliel accepted condolences for his death as one would for a close family member. His students said to him: Have you not taught us, our teacher, that one does not accept condolences for the death of slaves?
Rabban Gamliel said to his students: My slave, Tavi, is not like all the rest of the slaves, he was virtuous and it is appropriate to accord him the same respect accorded to a family member.
This does not contradict the principle that one does not accept condolences for slaves, as is explained in the Jerusalem Talmud: From here we see that a student is beloved like a son. A virtuous slave who was a student, like Tavi, is beloved like a son and therefore one may accept condolences for his death.
Tavi, the slave of Rabban Gamliel, is the most famous slave in the Talmud. Some go so far as to draw a parallel between Tavi, the slave of Rabban Gamliel, and Eliezer, the slave of Abraham. Rabban Gamliel was very fond of Tavi and appreciated his character and Torah knowledge. The Gemara relates that when Rabban Gamliel thought he had discovered a way to free Tavi he was overjoyed. Ultimately, though, he did not free him, due to concern over the prohibition to free a slave. Despite this, Rabban Gamliel treated him as a member of his family and, therefore, he accepted condolences when Tavi died.