Which is prioritized: marriage for the sake of chastity, or assisting one's father in paying off a usurious loan?

Marriage is a religious obligation for whoever longs for it, is capable of it, and fears falling into temptation, so much so that even a poor person borrows money to get married. As for your father’s debt, if it was not for an essential expense and your father was able to pay it off, then you are not obligated to pay it. Furthermore, prioritizing marriage for someone who fears falling into the forbidden takes precedence over paying off the father’s debt.