How is the Deposit to be Guarded?
Paul’s first pastoral epistle to Timothy ends with this command, “O Timothy, guard the deposit entrusted to you. Avoid the irreverent babble and contradictions of what is falsely called ‘knowledge’” (1 Tim 6:20).
In The Commonitories, fifth century monk, Vincent of Lérins, calls the church to heed Paul’s command to Timothy. But how is this to be done? How does the church guard the deposit of faith, in the midst of deceitful babble and contradictions? Vincent proposes that the church should cling to ancient tradition in the midst of novel ideas.
What Exactly is Tradition?
Before the church can guard the faith, they must be able to distinguish orthodox tradition from heresy. Vincent offers three principles that should guide the church and keep it safely in the bounds of orthodoxy. These principles are universality, antiquity, and consent. Regarding universality, the church should confess what has been confessed by the church all over the world. Concerning antiquity, the church should hold to the interpretation of its ancestors and church fathers. Finally, regarding consent, the church should hold the same meanings for words and propositions as have always been held.
Vincent sums those principles up well when he says, “Every care should be taken to hold fast to what has been believed everywhere, always, and by all.” . That is the ancient tradition that Vincent calls the church to hold to.
Vincent’s high view of tradition may lead some to believe that he held a low view of Scripture. That is not the case! He affirmed the sufficiency of Scripture, and The Commonitories regularly cite Scripture authoritatively. However, Vincent observed the reality of misunderstandings and distortions, and he saw the damage caused by theological errors in his time. Tradition is a protection, and it helps us understand Scripture rightly. It never trumps the Bible. However, without tradition biblical interpretation has no bounds, and anyone is free to interpret as they wish. This is obviously problematic. Because of this danger Vincent was calling the church to hold fast to tradition, for the sake of protecting Scripture and guarding the deposit entrusted to the church.
Dangers of Heresy
Looking at the words of Jesus, Vincent explains that heretics can sneak into the church undetected. Jesus warns, “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves” (Matt 7:15). The false prophets will often come twisting Scripture, in an attempt to lead people away from the true faith. 
Looking at the examples of Origen and Tertullian, Vincent also heeds the warning that even faithful men and women can fall into heresy when they neglect tradition. Origen and Tertullian were two of the most gifted writers and teachers of the early church. However, Vincent says of Origen, “he despised ecclesiastical traditions and the teachings of the fathers and interpreted some passages of Holy Scripture in a novel manner.  And Vincent says of Tertullian, “He was more eloquent than faithful”. Heresy enters the church in different ways, through the words of disguised wolves and the words of faithful men caught up in novelty.
The Bible is our ultimate guide, but we must be careful to understand it in light of tradition. Novelty is appealing—who doesn’t like to sound original? However, when discussing the Bible, novelty is dangerous. As the apostle Paul told Timothy to guard the deposit entrusted to him, and Vincent reminds us, Christians today should seek to guard the truth that has been passed down to us by generations of faithful witnesses.
 Vincent of Lérins. The Commonitories, trans. Rudolph Morris, vol. 7, FC (Washington D.C.: Catholic University of America, 1949), 270.
 Ibid, 315.
 Ibid, 301.
 Ibid, 302.