According to the Talmud, the treasury is a reference to 13 trumpet-shaped treasure boxes into which the money was thrown. They were located in the Court of the Women in the temple.
Once again, Elohim hardened Pharaoh’s heart. Elohim once again states His reason for this hardening. Future generations are to be told of this and He is to be glorified. That is also the reason behind Torah (Deut. 6:20-25). When we remove or discard His Torah, we are not giving Him the glory He so richly deserves.
Keep in mind that these plagues were an attack on the false gods of Egypt (Ex. 12:12, Num. 33:4). As this verse points out, Pharaoh would not allow the people to serve Elohim. The true conflict is between Pharaoh and his false gods opposing the worship of Elohim.
Abram departed as Elohim instructed him. It is interesting that Lot appears to be voluntarily participating in this huge step of faithfulness also. Abram was not a young man when he did this. He was 75 years old. We are not told how old Lot is at this time. The journey that Abram is going to take is at least 1500 miles