It is implied that the oppressed people cried out to God. Alternate translation: "when oppressed people cried out to you, you listened to them tell you what they need" (See: [[rc://en/ta/man/jit/figs-explicit]])
A strong heart represents courage, and making people's hearts strong represents encouraging them. Alternate translation: "you encourage them" or "you make them confident" (See: [[rc://en/ta/man/jit/figs-metonymy]])