ציטירנדיקער פּירוש אויף תהילים 144:11

Convert me on the condition that you teach me the entire Torah while I stand on one foot. One may ask: How could such a thought even enter his mind? It seems that the intention is that gentiles are attached to the level of falsehood, as it is said in Bava Batra (45a) that a standard gentile is presumed to be an extortionist, as it is written (Psalms 144:11), "Whose mouths speak falsehood, and whose right hand is a right hand of deceit." Similarly, it is stated in Niddah (45a). However, Israel is attached to the level of truth, and thus they are presumed to speak truthfully, as it is written (Zephaniah 3:13), "The remnant of Israel shall do no injustice, nor speak lies, neither shall a deceitful tongue be found in their mouth." Rabban Shimon ben Gamliel relied on this presumption in legal matters (Bava Metzia 107b). Furthermore, it is taught that truth stands firm while falsehood stands on one leg, as seen in the letters ק (kuf) and ר (reish), which have one leg each, while ש (shin) has a strong base, since liars must mix in some truth to make their falsehoods believable (Maharsha). This man, originally a gentile attached to falsehood, did not wish to abandon it even when learning Torah, which is why he asked to be taught while standing on one foot—symbolizing his adherence to falsehood. Shammai pushed him away with the builder’s cubit, indicating that Torah is the foundation of the world, and like a building, it cannot be erected on an unstable base, as stated: "Do not read 'your sons' (בניך) but 'your builders' (בוניך)" (Berachot 64a). However, Hillel answered him, "That which is hateful to you, do not do to your fellow," teaching that falsehood is inherently undesirable—no one wishes to be deceived, so one should not deceive others. Alternatively, Torah is upheld by three pillars: biblical commandments (De’oraita), rabbinic commandments (De’rabbanan), and enhancements of mitzvot (Hidur Mitzvah). The man wanted to observe only the first category, corresponding to one foot, but Shammai rejected this, as a complete structure requires all three levels, like Noah’s Ark with lower, middle, and upper decks. Hillel responded differently, comparing mitzvot to human limbs, which are also divided into three categories: vital organs (Torah commandments), beneficial organs (rabbinic laws), and aesthetic features (enhanced observance). Since one would not wish to lose even a non-vital limb, so too should one not neglect any mitzvot. Another explanation is that Torah consists of positive and negative commandments, corresponding to right and left, and just as a person needs two legs to walk, one must observe both. The man wanted to fulfill only negative commandments (passive observance) rather than actively performing mitzvot, akin to standing on one foot. Shammai pushed him away, teaching that a structure needs support on both sides. Hillel explained that just as one desires others to love what they love and hate what they hate, so too must one align with God’s will, observing both positive and negative mitzvot. Thus, Shammai rejected an unstable foundation, while Hillel provided a moral rationale to guide him toward a full acceptance of Torah.