Vow between Marcus and Silas

"Having endeavored to assist you, in return I expect a similar favor within a year and a day... may the Four Corners curse you if you prove false."

Pledge: Vow
Lesser Endeavor(-1) Marcus provided a discount to help Silas afford a weapon
Lesser Favor(+1) Silas will provide a similar favor to Marcus
Greater Curse(-3) The Four Corners of the Earth will punish Silas if he forgets or refuses
Greater Duration (+3) Silas has a year and a day to provide the favor

Accepted by Silas. Just to make sure that's clear.