It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that a man shot another with an arrow, causing his death. He had only one heir, and that was his maternal uncle. Sayyiduna Abu Ubaidah bin Al-Jarrah wrote to Sayyiduna Umar (may Allah be pleased with him) regarding this matter. In reply, he wrote back that the Prophet (peace and blessings be upon him) said: "Whoever has no mawla, Allah and His Messenger are his mawla, and whoever has no heir, his maternal uncle will be his heir."