It is narrated from Hazrat Abu Saeed (may Allah be pleased with him) that once the Prophet (peace and blessings of Allah be upon him) led the companions (may Allah be pleased with them) in prayer. After the prayer, a man came. The Prophet (peace and blessings of Allah be upon him) said, "Who will trade with him? Or who will give charity to him by praying with him?" Upon this, a man went and prayed with him.