Whenever the Deacon (or in the case of there being no Deacon, the Priest) completes a petition with “let us pray to the Lord”, the response of the faithful is “Lord, Have Mercy”. If the petition is completed with “let us ask of the Lord”, the response of the faithful is “Grant this, O Lord”. If the petition is calling to remembrance those who have gone to their eternal rest, the response of the faithful is “Eternal be their Memory” or some variation thereof. Another response of the faithful that is often not explicitly published in the text, but is an ancient pious custom is that of “Most Holy Theotokos, save us” when the petition calls us to remembrance of the Panagia, the Ever-Virgin Mary.
Throughout various services, you will commonly hear both All-Holy and Most Holy prefixed to the Theotokos. The difference is in the Greek construction of the associated words: Υπεραγια & Παναγια. (Yperagia, Panagia which mean All-Holy, and Most Holy). Regardless of English simplification, Theotokos does not mean Mother of God. This is evident in the term that is preserved for Mother of God in any icon of the Theotokos, which states in shorthand: Mitir Theou. Theotokos specifically refers to she who gave birth to God. There is something very intentional and theologically defining when we preserve the proper uses and definitions of these blessed terms. It irks me when they get mixed up, even when referring to the same person.
