The granite foundation of our heritage for all generations is set forth in no uncertain terms. Moshe emphasizes that everything rests on one basic fact: the nation itself witnessed the Divine revelation of Torah. Only take heed and guard your soul exceedingly, so that you do not forget the facts that your own eyes have seen, and so that they do not depart from your heart all the days of your life, and make them known to your children and your children’s children.
The historical fact of the Law Giving, as we experienced it with our own senses, is to remain alive forever in our hearts and minds, and it must be passed down to our children so that they too may take it to heart and pass it on to future generations.
There are two phenomena, each one unparalleled in its own right: A personal experience, perceived simultaneously by an entire nation is an unparalleled unique foundation for the historical fact of Revelation. The transmission of an entire nation from parents to children is a similarly unique unparalleled preservation of that experience. We are instructed here to “make it known” to our children — through the resoluteness and certainty born of our own personal experience. In this way, the authenticity remains even in the minds of the most remote descendants. Even the written record is authentic only because its contents have been handed down collectively by fathers to sons.
From this verse our Sages deduce a possible obligation to teach one’s grandchildren Torah, in addition to one’s children. Our Sages go on to praise this practice and declare that one who teaches his grandson Torah is considered as if he received it from Mount Sinai. The antecedent of “he”, however is unclear.
If “he” refers to the receiving grandson, the meaning is that what was received in the first generation shall be kept wholeheartedly by the receivers and then handed down to the next generation. It is as if that child himself stood at Mount Sinai.
If “he” refers to the father or grandfather, the meaning is that they are required to hand down the tradition with the clarity and conviction of people who themselves received the Torah at Mount Sinai.
Something else is also expressed here. When a person transmits the Torah to his children, he senses in his own life the faithfulness of the transmission. When he gives over what he learned from his own father, who learned it from his father, he is aware of the living authenticity of this tradition, reaching all the way back to Mount Sinai.
Notice how the Sages make this observation regarding a childwho learns Torah from his grandfather and not a child who learns from his own father. When a child learns the same Torah from his grandfather’s mouth which has already learned from his father’s, he sees that his father teaches him only what he himself received from his father, and that child draws the conclusion that all of the fathers reaching back for generations handed down only what they received from their fathers. In this way, the transmission itself cloaks the content with authenticity, enabling each generation to be an effective link in the chain beginning at Mount Sinai and continuing until the end of generations.
- Source: Commentary, Devarim 4:9