The previous dapim in Massekhet Yevamot discuss the classic rule of aseh dokheh lo ta’aseh – that performance of a positive commandment can push aside a negative commandment – of which the mitzva of yibum is an example. Our Gemara discusses cases that appear to be exceptions to that rule.
The commandment of honoring one’s mother and father is one of the most basic mitzvot in the Torah, one that appears in the Ten Commandments (see Shemot 20:11). What if a father or mother commands their child to perform an act forbidden by the Torah? Would the child be obligated to perform the forbidden act because of aseh dokheh lo ta’aseh – that the positive commandment obligating a child to listen to his or her parent overrides the negative commandment?
To this question the Gemara responds that the child cannot listen to his father or mother. The source for this is the passage in Vayikra (19:3), where we find that the commandment to be in awe of one’s parents – ish imo ve-aviv tira’u – is followed immediately by the commandment to keep the Shabbat – ve-et Shabtotai tishmoru. The juxtaposition of these two ideals is understood by the Gemara to teach kulkhem hayyavim bi-khevodi – that in a situation where the parent is obligated to show his awe of God by keeping a mitzva, he cannot order his child to transgress that mitzva.
The Gemara’s explanation appears to be logical and straightforward. Since the parent is not allowed to make this demand, it cannot possibly obligate the child. The Meiri argues that the case must be one where the request that is made is something that the parent needs, because if the parent demands that his child transgress a commandment for no reason, he falls into the category of a rasha for whom there is no mitzva of kibbud (honor). The Haggahot Maimoniyyot, one of the commentaries on the Rambam, reaches the opposite conclusion: that the case is one where the parent demands that the child transgress for no reason. Nevertheless, a simple oral statement does not make a person a rasha. Therefore the child remains obligated to listen to his father and mother in this case, were it not for the Gemara’s argument that kulkhem hayyavim bi-khevodi.