I learned that assistance given to the weak makes the one who gives it strong; and that oppression of the unfortunate makes one weak.
Attribution contested
Circulated everywhere as if you want to lift yourself up, lift up someone else, which appears in none of Washington's books, addresses or letters. This is the sentence in Up from Slavery it compresses. The paraphrase is not unfair, but it is not a quotation, and it drops the second half -- the claim that oppressing the unfortunate makes the oppressor weak -- which is the part he was actually arguing.