He said to him, "Most assuredly, I tell you, hereafter you will see heaven opened, and the angels of God ascending and descending on the Son of Man."

 So, then, even if Jesus Christ had never come into this world in bodily form, it would still have been possible for men to see God's word, God's Logos ( G3056) , God's reason in action. But, although the action of the word was there for all to see, men never recognized him. 