Righteousness presupposes rationality

But in opposition to pietism, the contrast or even incompatibility between righteousness and rationality must be rejected. Far from conflicting with rationality, righteousness presupposes it. If righteousness requires obedience to God, this obedience depends on understanding God's precepts. Sin is disobedience; and whatever stronger denunciations of sin are appropriate, sin can also be denounced as irrational. Then again, animals, which cannot sin, also cannot be righteous - the reason being that they are non-rational. Hence the image of God, which distinguishes man from animals, is basically logic. - Gordon H. Clark, The Philosophy of Gordon H. Clark volume 7

"The most important part of creation was the creation of man. The heavens and the earth, grand as they are, are, as it were, nothing but the stage setting for the actors in the Divine Comedy. The reason is that while nature displays the manifold wisdom of God, man bears God's image. Dogs don't. I still love dogs, dachschunds and St. Bernards. But God gave man a reasonable or rational soul. Man can learn mathematics. Dogs can't. And I still love dogs, Doberman pinschers and Toy Manchesters.
Further, dogs, not to speak of trees and stones, cannot be righteous or holy. To them the Ten Commandments and the Biblical requirements for worship do not apply. But man was created with the law of God written in his heart." - Gordon H. Clark, What Do Presbyterians Believe?, Pg. 59 - 60