פּירוש אויף בראשית 18:28

התשחית בחמשה WILT THOU DESTROY ON ACCOUNT OF THE FIVE — Will there not still be nine for each city, and You, the All-Righteous One of the Universe, can be counted with them to make up the original number of ten! (Genesis Rabbah 49:9).

I WILL NOT DESTROY IT IF I FIND THERE. He assured him that He would not destroy it if that number of righteous men will be found there. And He did not tell him, “Know that there is not such a number there as you said,” since their trial had not been completed, just as He said, I will go down now, and see.¹⁶⁷Verse 21 here.
Now Abraham did not know what would be done to them. Therefore, he rose early in the morning and looked towards Sodom,¹⁶⁸Further, 19:27-28. and upon seeing that they were destroyed, he knew that the required number of righteous men had not been there.

אולי יחסרון, if there are 5 righteous people missing from the 50 righteous people of whom I said that their presence should serve to save the city at this time, are You going to going to destroy the earth (surrounding these towns) and not forgive the place on account of the 45 righteous people that live there?”