6 For by means of the creation itself, the Word reveals God the Creator; and by means of the world [does He declare] the Lord the Maker of the world; and by means of the formation [of man] the Artificer who formed him; and by the Son that Father who begot the Son: and these things do indeed address all men in the same manner, but all do not in the same way believe them. But by the law and the prophets did the Word preach both Himself and the Father alike [to all]; and all the people heard Him alike, but all did not alike believe. And through the Word Himself who had been made visible and palpable, was the Father shown forth, although all did not equally believe in Him; but all saw the Father in the Son: for the Father is the invisible of the Son, but the Son the visible of the Father. And for this reason all spoke with Christ when He was present [upon earth], and they named Him God. Yea, even the demons exclaimed, on beholding the Son: “We know You who You are, the Holy One of God.” And the devil looking at Him, and tempting Him, said: “If You are the Son of God;” — all thus indeed seeing and speaking of the Son and the Father, but all not believing [in them].
Source: Adversus haereses (New Advent)