1. This festival requires us to instruct the people in the dogma of the Holy Trinity, and to strengthen both memory and faith concerning it. This is the reason why we take up the subject once more. Without proper instruction and a sound foundation in this regard, other dogmas cannot be rightly and successfully treated. The other festivals of the year present the Lord God clothed in his works and miracles. For instance: on Christmas we celebrate his incarnation; on Easter his resurrection from the dead; on Whitsunday the gift of the Holy Spirit and the establishment of the Christian Church. Thus all the other festivals present the Lord in the guise of a worker of one thing or another. But this Trinity Festival discloses him to us as he is in himself. Here we see him apart from whatever guise assumed, from whatever work done, solely in his divine essence. We must go beyond and above all reason, leaving behind the evidence of created things, and hear only God's own testimony concerning himself and his inner essence; otherwise we shall remain unenlightened. 2. Upon this subject the foolishness of God and the wisdom of the world conflict. God's declaration that he is one God in three distinct persons, the world looks upon as wholly unreasonable and foolish; and the followers of mere reason, when they hear it, regard every one that teaches or believes it as no more than a fool. Therefore this article has been assailed continually, from the times of the apostles and the fathers down to the present day, as history testifies. Especially the Gospel of St. John has been subjected to attack, which was written for the special purpose of fortifying this dogma against the attacks of Cerinthus the heretic, who in the apostolic age already attempted to prove from Moses the existence of but one God, which he assigned as reason that our Lord Jesus cannot be true God on account of the impossibility of God and man being united in one being. Thus he gave us the prattle of his reason, which he made the sole standard for heaven to conform to. 3. O shameless reason! How can we poor, miserable mortals grasp this mystery of the Trinity? we who do not understand the operation of our own physical powers--speech, laughter, sleep, things whereof we have daily experience? Yet we would, untaught by the Word of God, guided merely by our fallible head, pronounce upon the very nature of God. Is it not supreme blindness for man, when he is unable to explain the most insignificant physical operation daily witnessed in his own body, to presume to understand something above and beyond the power of reason to comprehend, something whereof only God can speak, and to rashly affirm that Christ is not God?