Abraham has a great sense of awe. There is a holy nervousness about him as he comes to ask: ‘Oh let not the Lord be angry.
Though it did not turn out to be the case that there were even 50 righteous people in the city or even 10, we learn that God may in this world for a time spare the wicked for the sake of the righteous. The fact that God agrees to spare so many on account of so few, shows that with God there is great patience and for the sake of the elect, he will bear long with the wicked.