"'till we get into the That-it-may-please-Thees'"
A 1596 edition of the Book of Common Prayer
Public DomainA 1596 edition of the Book of Common Prayer

Marian is talking about a section of the Book of Common Prayer, the guiding text used in many Church of England services.

In this section, the minister reads out a series of prayers using the formulation, "That it may please Thee"; the congregation responds, "We beseech Thee to hear us, good Lord".