If we were to consider it a philosophical argument, then we would understand that Anselm is trying to convince us of the validity of his thesis. If we were to look at it as a personal declaration of faith, then we are likely to detect no persuasion effort whatsoever. In fact, Anselm is far from convincing non-believers of the necessity to believe. His argumentation is not directed at having people believe in god. The manner in which he establishes the relation between faith and understanding is a clear sign in this direction. One can understand what Anselm is saying and be convinced of it only if he is a believer. At this point, it is safe to say that the importance of faith is fundamental. Under these circumstances, it becomes difficult to accept the view according to which the Proslogion is a philosophical argument. Were it such, its goal would be to persuade and it would definitely be impossible for it to rely so much an a variable that is so subjective, namely faith. This does not means that the strength of the logical argumentation is not relevant. It actually is. And what becomes even more striking is the power of persuasion that the argumentation in endowed with once the reader does not perceive it as a philosophical argument.
The ontological question is situated in a whole new dimension, in which the intellect is given the possibility to fulfill its capacities only once it has been contaminated with the spiritual. It is true that people are tempted to search for a logical demonstration of god's existence and Anselm's is somewhat convincing. However, he addresses an audience of believers. Therefore, the believers, being what they are, do not really need the logical demonstration in order to justify their faith (otherwise, they would not call themselves in that way).
The last issue of interest for the present discussion is the following: Hence he who possesses the more charity, will see God the more perfectly, and will be the more beatified.(- Thomas Aquinas, Summa theologiae I, q. 12, a. 6, resp.) Our goal is to explain the relationship between knowledge and love according to Thomas.
Looking at the quote from Aquinas, we realize that the most important element is charity. Charity is connected with kindness and therefore, with the good. What Aquinas suggests is that only the person who has a good heart will be able to know god. Not only that, but he will also be beatified, which means that he will receive the eternal grace of god, reaching a state of eternal happiness. The kindness can be interpreted as a manifestation of love. Hence, the direct connection between love and knowing god.
The dynamics is very interesting. Looking at the whole picture, we know that god is love. One of the most important attributes which are used in order to defined him is love. All his actions are believed to derive from this very reason. Since god is synonymous with good, then it results that love is synonymous with good.
We could find a similarity between the reasoning performed by Anselm and that perform by Aquinas. Anselm stated that only a believer can understand what god is. Aquinas on the other hand declares that only he who demonstrates charity can have access to the understanding of god. The question which we might ask ourselves now is: is a person who demonstrates charity and love for the others necessarily a believer? The answer is no. Does this matter? The answer is again negative.
God teaches men to love each other. A person who not only declares his love for the others, but actually manifests it through acts of kindness and charity demonstrates that he is just and good and this happens regardless of the fact if he believes or not. In fact, in the quoted phrase, Aquinas says nothing about the act of believing, he is referring only to the act of knowledge and beatification. This means that a heart who is ruled by love, is a pure heart which can provide its owner to access to the understanding of god. Not only that, but he is also likely to be beatified. Reading between the lines, we understand that if god is love and one man's heart is full of love, then god is in that man's heart. This is why he has access to knowledge. Because god can not be known, nor understood from the outside. The only route for knowledge is from the inside.
If love is the basis for knowledge, then we are brought to understand one more thing. Since love is irrational, then so is the knowledge of god. In other words, god is beyond the powers of the intellect. This is why he can be known only through faith or manifestations of him, such as love.
Last, but not least we might wonder about the reason for which one might choose to love the others. One might argue that this is one of god's teachings, but this is not enough in order to make love actually exist. It could be stated that it is an irrational choice as well and that it has no other end but itself. Which is exactly god's teaching. It is in this very choice that the divine essence is manifested, hence the possibility for its comprehension.