II. He entreats them to re-State the Faith as laid down in the Tome.
Wherefore, brethren most dear, let all attempts at impugning the Divinely-inspired Faith be entirely put down, and the vain unbelief of heretics be laid to rest: and let not that be defended which may not be believed: since in accordance with the authoritative statements of the Gospel, in accordance with the utterances of the prophets, and the teaching of the Apostles, with the greatest fullness and clearness in the letter which we sent to bishop Flavian of happy memory, it has been laid down what is the loyal and pure confession upon the mystery of our Lord Jesus Christ's Incarnation.
Source: Letters (New Advent)