Page "Gamaliel" Paragraph 6

As classical rabbinical literature always contrasts the school of Hillel to that of Shammai and only presents the collective opinions of each of these opposing schools of thought without mentioning the individual nuances and opinions of the rabbis within them, these texts do not portray Gamaliel as being knowledgeable about the Jewish scriptures, nor do they portray him as a teacher.

For this reason, Gamaliel is not listed as part of the chain of individuals who perpetuated the Mishnaic tradition.

Instead the chain is listed as passing directly from Hillel to Johanan ben Zakkai.