law itself, and can
change it when it wishes. Our Lord left His Church free to make certain
laws, just as they would be needed. It has always exercised this power,
and made laws to suit the circumstances of the place or times. Even now
it does away with some of its old laws that are no longer useful, and
makes new ones that are more necessary. But the doctrines, the truths of
faith or morals, the things we must believe and do to save our souls, it
never changes and never can change: it may regulate some things in the
application of the divine laws, but the laws themselves can never change
in substance.

*127 Q. In whom are these attributes found in their fullness?
A. These attributes are found in their fullness in the Pope, the visible
head of the Church, whose infallible authority to teach bishops,
priests, and people in matters of faith or morals will last to the end
of the world.

128 Q. Has the Church any marks by which it may be known?
A. The Church has four marks by which it may be known: it is one; it is
holy; it is catholic; it is apostolic.

*129 Q. How is the Church one?
A. The Church is one because all its members agree in one faith, are all
in one communion, and are all under one head.

The Catholic Church is "one," first in government and second in
doctrine. In government every pastor has a certain parish or territory
in which all the people belong to his congregation--they form his flock.
He has to take care only of these, to teach them, give them the
Sacraments, etc. He has not to be responsible for those outside his
parish. Then over the pastor we have the bishop, who looks after a
certain number of pastors; then comes the archbishop over a certain
number of bishops; next comes the primate, who is head of all the
archbishops in the country; and over all the primates of the world we
have the Holy Father. Thus, when the Holy Father speaks to the bishops,
the bishops speak to the priests, and the priests to the people. The
Church is therefore one in government, like a great army spread over the
world. We can go up step by step from the lowest member of the Church to
the highest--the Holy Father; and from him to Our Lord Himself, who is
the invisible head of all. This regular body of priests, bishops,
archbishops, etc., so arranged, one superior to the other, is called the
hierarchy of the Church.

The Church is one also in doctrine--that is, every one of the three
hundred million of Catholics in the