5 Paul was a heaven, when he said: “Our conversation is in heaven.” James and John were heavens, and then were called “sons of thunder”; and John, being as it were a heaven, saw the Word with God. The Lord Jesus Himself was a heaven of perpetual light, when He was declaring the glory of God, that glory which no man had seen before. And therefore He said: “No man has seen God at any time, except the only-begotten Son, Who is in the bosom of the Father, He has declared Him.” If you seek for the handiwork of God, listen to Job when he says: “The Spirit of God Who has made me.” And so strengthened against the temptations of the devil, he kept his footsteps constantly without offense. But let us go on to what follows.
6. “Day,” it is said, “unto day utters speech.” Behold the true days, where no darkness of night intervenes. Behold the days full of life and eternal brightness, which uttered the word of God, not in speech which passes away, but in their inmost heart, by constancy in confession, and perseverance in their witness.
Source: Letters (New Advent)