YeHoVaH reasoned concerning the need to share with Abraham what He was about to do to Sodom, where Lot lived, and Gomorrah.  Among the reasons was that Abraham was a prophet; he would become a great and mighty nation and all the nations of the earth would be blessed through him; Abraham lived in the region where YeHoVaH was about to judge the people; and Abraham had fought to save the people of Sodom and Gomorrah and returned them to their homeland.  YeHoVaH gave Abraham the opportunity to intercede and negotiate on behalf of the people just as he had risked his life and fought to save them.