There is a dispute between Rabbi Shimon Bar Yochai and his students how an individual saying the Shema can complete the count of 248 words when saying Shema, when the Shema itself has only 245 words.
When there is a minyan, everyone agrees that the Chazan repeats the words ‘Hashem Elokeichem Emes”. When someone davens alone, Rabbi Shimon bar Yochai holds that they should repeat the words “Ani Hashem Elokeichem” “I am Hashem your G-d”, before adding the word Emes. However, his students hold that one cannot repeat these words.
The Frierdike Rebbe explains this in a most beautiful manner. It is stated in the Zohar, that Rabbi Shimon bar Yochai said that he is “bound up with Hashem in one knot’’. This means to say that Rabi Shimon bar Yochai was on such an elevated level that he was totally connected to Hashem. Therefore, according to him, an individual can say the words “I am Hashem your G-d", which, although is obviously referring to Hashem, sounds as if the person is saying he is G-d. But his students, who were not on such a high level, were of the view that we are not able to say this.
Even though (according to Nusach Ariza”l) we repeat the words “Ani Hashem Elokeichem” like the opinion of Rabbi Shimon bar Yochai, we say it quietly and not out loud. But on Pesach, the essence of Hashem – the Ein Sof, shines in every Jew’s soul. Therefore, each person can say “Ani Hashem Elokeichem” out loud without concern. This is why we say out loud at the Seder “I am Hashem... I am He and no other.”
~ First night Seder 5697
