The verse "Shema Yisrael" appears in Deuteronomy chapter 6, 4 and expresses the basic idea of Yehudah as the most basic declaration of faith and love of the Jewish people to God, which is one and only. This verse is also said

in extreme cases, for example, in cases of death for Kiddush Hashem and at the end of the Yom Kippur prayer at the conclusion of the prayer. Jacob before his death gathered all his sons and swore them to believe in one God. Since all the children of Jacob - Israel do not forget their oath and say the verse: