Sanhedrin 22 - One's First Wife
Every Jew has to write (or hire a scribe to write) a Torah scroll for himself, following " And now, write for yourself this song ..." - but a king writes a second, small one, to carry around.
No one may ride on the king's horse, no one may sit on his throne, and no one may use his scepter. No one may observe the king when he is getting a haircut (every day), when is undressed, or when he is in the bathhouse, following " You shall surely place upon yourself a king ..." - the awe of the king must be upon you.
Nobody but another king can marry a king's wife. Thus Avishag, whom David never married, was permitted only to Solomon. Why did David not marry Avishag? Because for that he would have to divorce one of his eighteen wife, and divorce is harsh. Whenever anyone divorces his first wife, even the Altar sheds tears on his account .
Art: Konrad Witz - King Solomon and the Queen of Sheba