Now write this song for yourselves and teach it to the Bnei Yisrael, place it in their mouth.
Be’er Yosef – What does the Torah imply by speaking not only of teaching, but placing Hashem’s words in their mouths? The gemara differentiates between the two commands, and offers an illustration of what the more onerous requirement entails.
Teaching, says the gemara, requires far more than offering material, more than making it available to the student. You’ve only taught when the student grasps the content. Placing it in their mouth demands even more. The student must grasp and retain the material so well that he can relate it with verbal ease and facility. If he still stumbles when trying to explain it verbally, he doesn’t grasp it well enough, and his teacher has not completed his job.
The gemara then relates how R Preida fulfilled the requirements of our pasuk – and then some. A particular student only retained R Preida’s teaching if it was taught to him 400 times. R Preida complied. Once, the student didn’t master the material even after this repeated instruction. He asked the student if there was a reason for this. The student responded that he had heard his rebbi announce that he would have to leave to attend to some mitzvah concern. This put him ill at ease; he worried that his rebbi might soon be absenting himself. The very thought made him lose focus.
R Preida dutifully taught the student another 400 times, whereupon a heavenly voice offered him the choice of 400 years to be added to his life, or that he and his generation would receive eternal life in olam habo. R Preida chose the latter option; Hashem instructed that he be given both rewards.
While the story has a happy ending, it does not seem to make too much sense. What was so extraordinary about choosing the next world over this one? Can there be any comparison to anyone who understands the slightest of what they are? Don’t Chazal teach that one moment in olam habo is better than the all the benefit and enjoyment in this world? Was there really a choice?
A similar story regarding Shlomo seems similar, but is really a distraction from our question. When Hashem asks Shlomo what gift he would like to receive – essentially granting him one request – Shlomo asks for wisdom and discernment with which he can judge the people, and distinguish between good and evil. Hashem is pleased with Shlomo’s wise choice. He praises Shlomo for not having chosen instead to live a long life, or to accumulate much wealth, or to be given great honor, or victory over his enemies. By way of reward, Hashem grants Shlomo’s wish, and tells him that He will grant him as well all the blessings Shlomo could have asked for and didn’t. While this story seems to run parallel to ours, it really does not. Shlomo was a child of twelve at the time. For him, making the proper choice was a challenge; it should not have been for R Preida.
A closer reading shows that it was indeed a monumental challenge to R. Preida. Chazal describe a person who serves Hashem entirely out of love. He doesn’t factor in, or think twice about his personal reward; he focuses only on the privilege of being able to do Hashem’s bidding. R Preida was certainly such a person. To him, there was no choice – but not in the way we first imagined. R Preida would have found it far more attractive to live longer so that he would be able to serve Hashem in the performance of mitzvos. This would not be possible in the grave, even with his neshamah basking in the radiance of the Shechinah in olam habo.
To someone like R Preida, olam hazeh was therefore far more precious than olam habo. Why, then, did he choose the opposite? Because the olam habo included not only himself, but his entire generation. As attractive as extra years of mitzvah-oriented living were, he would not deny the gift of eternal life to those who lived around him. He selflessly turned down the greatest gift he could conceive, in order to bestow a great benefit on his community.
Hashem valued his selflessness, his chesed, and his insight. He therefore instructed that both blessings be made available to R Preida.
 Based on Be’er Yosef, Devarim 31:19
 Eruvin 54B
 Melachim1 chap. 3