From the video below:
“The old liturgy was never prohibited. We need only norms: How in peace apply it? …so that the reformed liturgy is the normal liturgy of the community of the Church, but the other is always a valid liturgy of the Church—can be used—but in obedience to the bishops and the Holy Father.”
Also from that 2003 interview:
“I think it’s important to […] demonstrate the continuity of the Church. We are today not another Church as 500 years ago; it’s always the same Church. And what’s at one time holy for the Church is always holy for the Church, and is not in another time an impossible thing.”