rational

Neither endeavour to let anything appear rational to yourselves apart;

Then Adam held out his hand, and put it into Satan's hand; when Satan said unto him, "Say, now--so true as God is living, rational, and speaking, who raised the heavens in the space, and established the earth upon the waters, and has created me out of the four elements, and out of the dust of the earth--I will not break my promise, nor renounce my word."