Although he was poor, he refused to accept the money.
Literal
Poor [topic-は] was [but-が] that money [topic-は] accept [tried-not-to-受け取ろうとしなかった].
貧しくはあったが uses contrastive は inserted into the く-form of 貧しい to set up the contrast — 'poor though he was.' 受け取ろうとしなかった combines the volitional form with ~としない meaning 'refused to' or 'would not.' A story of principled refusal.