John Calvin Commentary Genesis 9:23

"And Shem and Japheth took a garment, and laid it upon both their shoulders, and went backward, and covered the nakedness of their father. And their faces were backward, and they saw not their father`s nakedness." — Genesis 9:23 (ASV)

And Shem and Japheth took a garment. Here the piety, as well as the modesty, of the two brothers is commended; who, so that their father's dignity might not be lowered in their esteem and that they might always cherish and preserve the reverence they owed him, turned away their eyes from the sight of his disgrace.

Thus they demonstrated the regard they showed for their father’s honor, by supposing that their own eyes would be polluted if they voluntarily looked upon the nakedness by which he was disgraced. At the same time, they also paid regard to their own modesty. For (as it was said in Genesis 3:1) there is something so inexplicably shameful in human nakedness that hardly anyone dares to look at himself, even when no witness is present.

Their actions also censure the impious rashness of their brother, who had not spared his father.

Hence, we may learn how acceptable to God is that piety, an example of which, recorded here, receives significant commendation from the Spirit. But if piety towards an earthly father was such an excellent virtue, and so worthy of praise, with how much greater devotion ought the sacred majesty of God to be worshipped?

The Papists make themselves ridiculous when they desire to cover the filthiness of their idol, indeed, the abominations of their whole impure clergy, with the cloak of Shem and Japheth. I will not elaborate on how great the difference is between the disgrace of Noah and the execrable vileness of so many crimes which contaminate heaven and earth. But Antichrist and his horned bishops, with all that rabble, must first prove themselves to be fathers if they wish for any honor to be paid to them.