Lefebvre: Marks of the Church only with SSPX, not with others
"Where is the visible Church? The visible Church is recognized by the signs that she has always given for her visibility: she is One, Holy, Catholic and Apostolic. (…) where are the true marks of the Church? Are they more in the official Church (it is not the visible Church, it is the official Church) or with us, in what we represent, what we are?
If there is still any visibility of the Church today, it is thanks to you. These signs are no longer found in others. There is no longer any unity of faith among them, yet it is faith that is the basis of all visibility of the Church. Catholicity is one faith in space. Apostolicity is one faith in time and holiness is the fruit of faith, which materializes in souls by the grace of God, by the grace of the sacraments.
It is quite wrong to consider ourselves as if we were not part of the visible Church. […] is to make a mistake in equating the official Church with the visible Church." Conference given on 9 September 1988