#He spoke to him

"Abraham spoke to Yahweh"

#if there are forty found there

This means "if you find forty righteous people in Sodom and Gomorrah."

#He replied

"Yahweh answered"

#I will not do it for the forty's sake

"I will not destroy the cities if I find forty righteous people there"

#thirty

"thirty righteous people" or "thirty good people"

#Look

The phrase "Look" here draws attention to the surprising information that follows.

#I have undertaken to speak

"I have been so bold to speak to you." AT: "Pardon me for being so bold as to speak to you" or "Excuse me for daring to speak." See how this is translated in [[:en:bible:notes:gen:18:27|18:27]].

#twenty

"twenty righteous people" or "twenty good people"