Sforno comments concerning the young children’s hearing and learning, “The young children assembled at the time of Hakhel, who are too young to be capable of appreciating the words read by the king, will nonetheless sense that something of significance is transpiring. Eventually, they will inquire and learn as they mature, for their curiosity and desire to know will have been aroused.” This explanation illuminates the practical benefit of attending the Hakhel for young people. The experience will ultimately cause them to pursue the Torah’s teachings when they mature and become capable of absorbing its lessons.
We have no idea what the mind can grasp and what remains indelibly ingrained in one’s subconscious. Horav Chaim Zaitschek, zl, cites Chazal (Shabbos 68a) who teach that a young child that was taken captive by pagans, during which he transgressed a multitude of prohibitions, a child who knew neither what a Jew is nor what his obligations are, will one day, when he is reinstated and made aware of his heritage, bring a sin-offering for each transgression. Mindboggling! The child knew nothing. Why should he be obligated to offer a korban chatas al shiggegaso, sin-offering, for his inadvertent sin? Rav Zaitchik explains that something, a mah she’hu, minimal, insignificant amount, remained engraved in his subconscious mind, something he heard, saw, experienced when he was but an infant – which will remain with him, regardless of the environment that he is in. Once he matures, his subconscious will come to the fore and motivate him to seek clarity concerning what is “bothering” him.
We find throughout Chazal (Yerushalmi Kesubos 5:6), that our sages relate events that occurred, or identities of people whom they saw as infants. It meant nothing then, but, years later, it arouses questions and inspires life lessons. We know neither what the eye sees nor what the mind grasps, but obviously the Torah feels that a spiritual experience can impact the mind of even the youngest child. It is like a seed that germinates and takes hold over time, until it bursts forth as a finished product. Every opportunity to avail our children of wholesome, spiritual experiences should be embraced. Furthermore, when they spend their free time exposed to foolishness (however kosher) via media, this is what will fill their subconscious and motivate their minds. Honestly, it is a “no-brainer.”