Keys are not an uncommon bearing in heraldry. In the logo of the Swiss bank UBS for example, there are three keys which stand for confidence, security, and discretion.
Keys are common also in the insignia of religious houses and sees. Most frequently, two Crossed Keys are associated with St. Peter and the keys of heaven. But why two keys? Are there two locks on the gates of heaven?
The answer to this is in Matt. 16:18-19, which is not so easy to understand and even less easy for different Christian denominations to agree the precise meaning. For sure, Christians do agree that our sin locks us out of heaven. Christ's passion unlocks these gates and allows us to enter.
Keys appear, either singularly or in pairs, in a number of church logos. For example:
So keys are not exclusively Roman Catholic but they are often associated with Rome because of its strong link to St. Peter.
Included in the papacy's coat of arms are two symbolic keys forming a St. Andrew's Cross. One key is silver and the other gold. These keys appear on the coat of arms of the Roman Catholic Holy See, the coat of arms of the Vatican City, and the coat of arms of every pope since the 12th century.
The keys represent two separate functions: One, the power to bind and to loose on earth (represented by the silver key); and two, the power to bind and to loose in heaven (the gold key). These are a reference to St. Matthew's Gospel:
|18||And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it.|
|19||I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.|
|Matt 16:18-19 (NET)|
In ecclesiastical heraldry, the keys symbolise the spiritual authority1 of the Papacy as Vicar of Christ. In other words, his authority and responsibility to teach what is lawful or unlawful. Now as any educationalist knows, the success of a student depends not only on the teacher's ability to teach but also on that student's willingness to learn.
The same can be said for Christians. The Church can teach what is lawful or unlawful but each individual must be willing to accept what is taught.
The number of keys in the Scriptures is not specified. The two keys in the papal insignia are in reference to the salvation, or the damnation, of our soul whilst we live this earthly life. If we are bound in the love of Jesus Christ on earth, then we will have our place in heaven. But if we allow ourselves to be loosened from Jesus Christ, then we will have no place in heaven.
And what does it mean to be "bound in the love of Jesus Christ"? Well, the two keys are arranged in the shape of a cross, and that gives us a clue. See Meaning of the Cross