16 Christ our Lord, foreseeing the present state of things, definitely stated in his sublime Sermon on the Mount, what are the real "beatitudes" of man in the world; and thereby He may be said to have laid down the foundations of Christian philosophy. Even in the eyes of the adversaries of the faith they are full of incomparable wisdom, and form a most complete religious and moral system; and certainly all would admit that before Christ, Who is the Very Truth, no such teaching in those matters had ever been uttered with such weight and dignity, or with such a depth of love.
Source: Ad Beatissimi Apostolorum (Vatican.va)