Since remaining in Sedom was fraught with danger, why did Lot delay?
Rashi: The answer is human nature - he was being told to leave without his money, a request that too much for him.
Why indeed, was Lot not permitted to take his money with him?
Rashi: Because on whatever basis HaSh-m was saving him, it was sufficient to save him, but not his money, as the next Pasuk hints - "Save yourself! (i.e. but not your money)" (19:17).
What is the significance of 'HaSh-m's pity' here?
Ramban #1: To teach us that Lot was not being spared on his own merit, but because HaSh-m had taken pity upon him.
Ramban #2: The angels were pushing him to escape before HaSh-m's patience ran out and he would be destroyed together with the other inhabitants of Sedom.
Seforno: Even though his salvation was based on the merit of Avraham, 1 his delaying tactics would have brought about his own death, were it not for the fact that HaSh-m had taken pity on him - bearing in mind that his procrastination was due, not to an act of rebellion, but to his laziness.
See 19:29.
Seeing as Refa'el was sent to save Lot, and Gavriel to overturn Sedom, what right did the latter have (here and in the following Pesukim) to assist in leading Lot out of the town?
Ohr ha'Chayim: He only assisted Refa'el, and we have a principle, 'Someone who merely assists is not considered as having performed the act'. Moreover, the reason that he assisted was because Refa'el would not have allowed him to overturn Sedom as long as Lot was still inside the town, in which case what he did was a preparation for the destruction, which was therefore part of his Shelichus. 1
Compare to Gur Aryeh (to 18:2); Hadar Zekenim (to 19:13).
The previous verse called them angels. Why does it say "the men held Lot"?
Moshav Zekenim: Angels are of fire. They needed to assume a human form, lest they burn him when holding him.
QUESTIONS ON RASHI
Rashi writes: "'And he tarried' - to rescue his money." Perhaps he delayed in order to persuade his married daughters to leave the city?
Gur Aryeh: To "tarry" means to delay for an invalid reason; to rescue something that is not worthy of being rescued.
Rashi writes: "'And the men grabbed hold their hands' - One [angel] had the mission to rescue them, and the other to overturn Sedom." If so, why is this verse in the plural (meaning that both angels led them out of the city)?
Gur Aryeh #1: Lot was attempting to save his money (Rashi), but he was unworthy of this (Rashi to 19:17); his money was to be destroyed along with the city. The angel assigned with destruction now led Lot away, to prevent him from doing so.
Gur Aryeh #2: It was impossible for the angel to destroy the city until Lot would leave. 1
Refer to 18:2:1.2:1.