First trying to give tzedakah as a gift, and then making it a loan if the pauper insists: Ketuvot 67b
If a pauper refuses to accept tzedakah, giving it as a loan and then forgiving it: Ketuvot 67b
The mitzvah applies even if the recipient isn't making an effort to support himself: Bava Metzia 31b
Priorities for who receives a loan first: Bava Metzia 71a
Related issues
Blessing for one who forgives a debt: Ketuvot 19a
Is a lender considered a "paid guardian" for the collateral he holds, because of the reward he receives for philanthropically lending money: Bava Metzia 80b, 81b-82a
Encouraging a lender to make money from the collateral and use it to decrease the amount a pauper owes him: Bava Metzia 80b
Considering the return of a pauper's collateral as a form of tzedakah: Bava Metzia 82a