Oh?
Just HOW do you KNOW this?
Because we have contemporaries of the Apostles not mentioning it at all. Doesn’t it make sense that if Jesus actually wrote something it would not only be referenced, but preserved? Should it have be destroyed, wouldn’t it have been a major catastrophe, noted by believers? Wouldn’t the possession of such a text by the Apostles reduced any kind of confusion among the Gentiles? Finally, wouldn’t the Gospel writers have made note, and referenced it?