Nishmat

[1] Shochen Ad, שׁוֹכֵן עַד (Translated as He Who abides forever or He Who dwells in eternity) is a short prayer which is embedded in Ashkenazi texts of Nishmat.

According to the Western Ashkenazic rite, the chazzan begins ha-gibur la-nezach on Passover, Hakel B'tzatzumot on Shavuot and ha-gadol bi-khvot shemecha on Sukkot.

[3] On the High Holidays, the chazzan begins on the word Hamelekh (המלך) within that verse, as during these days, an emphasis is placed on recognition of God as King.

[4] It is also described in Sefer HaChaim that loudly chanting the word Hamelekh has the effect of driving away accusers from the throne of judgement.

[5] Additionally, the letter ה is dropped off the word היושב, alluding to the fact that now God is sitting on the throne.

The second word in each of these verses begin with the Hebrew letters י,צ,ח,ק, forming the acronym יצחק (Yitzchak, Isaac).

In the Talmud, Rabbi Yochanan bar Nafcha (180-279 CE) states that Nishmat should be recited during the Passover Seder after Hallel.

[26][27] The latter theory is often cited in conjunction with a rabbinic legend that Simon Peter was an agent of the Sanhedrin who infiltrated early Christianity in order to differentiate it from Judaism so that Jews would not be easily attracted to it.