Western monasticism since, and in his day, he was the greatest of saints. Considered the last of the Fathers of the Church, St. Bernard left an unparalleled legacy behind him.
So what can Catholics learn from him today? Oftentimes, I have noted a current of thought out there that seems to think that the Middle Ages has nothing to say to modern man as he is now; while some interest has been revived in the Church Fathers, it seems that the Middle Ages is still viewed as an era of the Church which is no longer relevant outside of a few, such as St. Thomas Aquinas.
The Middle Ages represents the very height of Catholic thought, theology, and mysticism. St. Bernard, in many respects, is the greatest of the mystical writers and theologians. His writings are the farthest thing from dry - indeed, they seep with "the most tender devotion to Our Lord and His Blessed Mother."1
St. Bernard teaches us to have greater devotion and love for the Blessed Virgin Mary in a similar vein to the great Syrian Doctors such as St. Ephrem and St. John of Damascus. Ironically, St. Bernard's writings were greatly popular amongst the early Protestant Reformers, despite his ardent love for the Mother of God. If one wishes to cultivate a greater love for the Blessed Virgin Mary, then St. Bernard is a most excellent teacher in this.
For those who wish to deepen their spiritual life in general, again, St. Bernard is an excellent choice as a guide through all manner of spiritual struggle and hardship. Questioning his own motives as to why he had chosen the life of a monk everyday, St. Bernard teaches us to take our own lives as Christians very seriously. His writings help us to avoid pitfalls into sin and to stay on the straight and narrow path to heaven, describing the spiritual combat that we all go through with the same keen insight and understanding as the Desert Fathers before him.
And if one wants to deepen their understanding of Scripture, it is St. Bernard again who is nearly without parallel. Often, I mention Origen as helping me to read Scripture in a whole new light (several lights, in fact), but I am amiss in omitting St. Bernard's influence on me as well. To read St. Bernard and see how he so easily and artistically weaves together the words of Scripture is an absolute treat - one cannot help but learn from this, and truly begin to read Scripture as an organic and living whole rather than a series of separate books without connections between each other.
St. Bernard is still one of the greatest teachers of the Gospel. His monastic example, his devotional and mystical theology, and his masterful understanding of Scripture all place him at the height of Catholic thought.
1 - The New Catholic Dictionary, "Bernard of Clairvaux", 1929 ed.