Commentary for Kiddushin 120:7

R. Yehudah could answer you that this baraita accords only with Rabbi [Yehudah Hanasi] according to whom when one says “On condition” the statement takes effect immediately. But R. Yehudah (the amora) holds like the other rabbis, according to whom “On condition” is a stipulation and the statement won’t take effect until the condition is fulfilled. This is a common way of solving difficulties—ascribe the tannaitic source to a minority position and then claim that the majority disagreeץ