Midrash Tannaim

'Sufficient' - If one encounters a poor person, one is obligated to fulfill that person's needs, as it says: 'sufficient.' If the giver doesn't have enough, they should give according to their ability. How much? Up to one-fifth of one's property, the choicest form of the commandment; one-tenth of one's property, average; less than that, selfish. Thus: God says to Israel, 'My Sons, whenever you give sustenance to the poor, I impute it as though you gave sustenance to me, for it says, My Bread.' Does then, God eat and drink? No, but whenever you give food to the poor, God accounts it to you as if you gave food to Him.⁠a

Another idea, “Do not show favoritism” (Deut. 16:19) - alas this was already said [in Deut 1:17] “You shall not be partial in judgment: hear out low and high alike. Fear no one, for judgment is God's. And any matter that is too difficult for you, you shall bring to me and I will hear it.” Rather, this verse is a warning to the sages when the students sit before them, do not be a teacher to one while setting aside another. If they did this, it is like they worshipped idols. On this it was written after it [in subsequent verses], Justice, justice you shall pursue (Deut 16:20), do not make for yourself an idol. (Deut 16:21). “Justice, justice you shall pursue.” (Deut 16:20) One might think that if one leaves the court innocent we (can) bring that person back to (find them) guilty, but that would be incorrect as the text teaches us Justice, justice you shall pursue; And if one left (the court) guilty, from where do we know that we bring that person back to (find them) innocent? The Torah inference teaches us, Justice, justice you shall pursue.