Letter 129: Your letter, beloved, which our brother and fellow bishop Nestorius duly brought us, has caused me great joy. For it was seemly that such an epistle should be sent by the head of the church of Alexandria to the Apostolic See, as showed that the Egyptians had from the first learned from the teaching of the most blessed Apostle Peter through his b...

Pope Leo the GreatProterius, of Alexandria|c. 456 AD|leo great
arianismchristologyillnessimperial politicspapal authority
Theological controversy; Imperial politics; Church council

Leo, Bishop of Rome, to Proterius, Bishop of Alexandria.

I. He commends Proterius's persistent loyalty to the faith

Your letter, beloved, which our brother and fellow bishop Nestorius duly delivered to us, has given me great joy. For it was fitting that such a letter should come from the head of the church of Alexandria to the Apostolic See -- one that demonstrated that the Egyptians had learned from the beginning, through the teaching of the most blessed Apostle Peter and his disciple Mark, the same faith that the Romans have always held: that "there is no other name under heaven given among men by which we must be saved" than the name of our Lord Jesus Christ (Acts 4:12).

But because "all men do not have faith" (2 Thessalonians 3:2), and the crafty Tempter delights in nothing more than poisoning unwary minds with errors opposed to Gospel truth, we must strive through the powerful teaching of the Holy Spirit to prevent Christian understanding from being perverted by the devil's lies. Against this danger the rulers of the churches must be especially on their guard, shielding the minds of the simple from falsehoods disguised by a certain appearance of truth.

"Narrow and steep is the way that leads to life" (Matthew 7:14). Those who would lead others astray seek to entrap them not so much by monitoring their conduct as by corrupting the meaning of doctrinal statements through some very slight addition or alteration. Sometimes a single word changed in a sentence transforms right faith into heresy.

II. He reaffirms the Chalcedonian definition

Hold fast, therefore, beloved brother, to the faith that was confirmed at Chalcedon: that our Lord Jesus Christ is one Person in two natures, truly God and truly man, born of the Father before all ages as to His divinity, and born of the Virgin Mary in the last days as to His humanity, consubstantial with the Father in His divine nature and consubstantial with us in His human nature. This is the faith that Peter confessed, that the Apostles preached, that the Fathers defended, and that the Council has now solemnly confirmed.

Watch over your flock with the care that so ancient and venerable a see demands, and let the memory of Mark, who received his mission from Peter, inspire you to preserve undiminished what the Apostles established.

Dated from Rome.

Modern English rendering for readability. See the 19th-century translation or original Latin/Greek for scholarly use.

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