Imperishable duration of the Church and her immutability until the end of time. The First Vatican Council declared that the Church possesses "an unconquered stability" and that, "built on a rock, she will continue to stand until the end of time" (Denzinger 3013, 3056). The Church's indefectibility, therefore, means that she now is and will always remain the institution of salvation, founded by Christ. This affirms that the Church is essentially unchangeable in her teaching, her constitution, and her liturgy. It does not exclude modifications that do not affect her substance, nor does it exclude the decay of individual local churches or even whole dioceses.