Born in Fontaines, France, Bernard entered the monastery of Citeaux at the age of twenty. In 1115 he was sent by St. Stephen Harding, third abbot of Citeaux, to found a new monastery at Clairvaux where Bernard himself became abbot. At Clairvaux the saint "insisted on the importance of a sober and restrained lifestyle, in food, in clothing and in the structures of the monastery, at the same time encouraging support and assistance for the poor", the Holy Father explained.

From Clairvaux, where the community grew steadily, Bernard corresponded regularly and often with people of all kinds, and wrote a large number of sermons and treatises. As of 1130 he also concerned himself with serious questions affecting the Holy See and the Church. With his writings he combated the heresy of the Cathars who, by spurning matter and the human body, also spurned the Creator. Likewise, he "defended the Jews, condemning the ever more widespread outbreaks of anti-Semitism".

The two central aspects of the saint's doctrine concern Jesus Christ and the Virgin Mary. He "did not introduce novelties to the academic discipline of theology but, with great decisiveness, likened the theologian to the contemplative and the mystic", in the belief that "true knowledge of God consists in a personal and profound experience of Jesus Christ and His love.

"This", the Pope added, "applies to all Christians. Faith is first and foremost an individual and intimate encounter with Jesus, it means experiencing His closeness, His friendship, His love". Thus Bernard was in no doubt that "through Mary we are led to Jesus", and he clearly demonstrated "the privileged place of the Virgin in the economy of salvation, thanks to her entirely unique participation in the sacrifice of her Son".

Even today St. Bernard's ideas "stimulate not only theologians but all believers. At times we think we can resolve the fundamental questions about God, mankind and the world using only the power of reason. St. Bernard however, solidly rooted in the Bible and the Fathers of the Church, reminds us that without a profound faith in God, nourished by prayer and contemplation, ... our reflections upon the divine mysteries risk becoming a vain intellectual exercise and lose their credibility".

Benedict XVI concluded: "Theology defers to the 'science of the saints' - to their intuition concerning the mysteries of the living God, to their wisdom (a gift of the Holy Spirit) - who become a point of reference for theological thought. ... In the end, the most authentic figure of theologian and of evangeliser remains that of St. John, who placed his head against the Master's heart".