Genesis 18:30

And he said unto him, Oh, let not the Lord be angry, and I
will speak
He feared, through his importunity, he should be wearisome to him and incur his displeasure; this being often the case among men, especially when inferiors are soliciting their superiors, and, not content with one favour, are pressing for more:

Peradventure there shall thirty be found there;
the abatement is larger than before; he only made an abatement of five at a time, now ten at once, and so he proceeds;

and he said, I will not do [it], if I find thirty there;
not destroy the place for their sake.