1)
What do we learn from "Pesach Picha l'Ilem"?
1.
Gitin 37b: Some say that if a lender claims payment after Shemitah, we ask 'perhaps you had a Pruzbul, and lost it?' Malbim - one who cannot make his claims, you must claim for him.
2)
Why does it say "[El Din] Kol Bnei Chaluf"?
1.
Rashi: This refers to orphans - their help (fathers) passed [from the world].
2.
Malbim: These are people whose Mazal changed, and they lost their property, and they have Din and Devarim (claims) against their oppressors.