Al-Zuhri narrates that a man (Sayyiduna Sunayn Abu Jamilah (may Allah be pleased with him)) came to his family, having picked up a foundling. He went to Sayyiduna Umar (may Allah be pleased with him) and mentioned it to him. Sayyiduna Umar (may Allah be pleased with him) said: "Perhaps this is some evil matter." The man said: "This child was picked up only while I was absent." Sayyiduna Umar (may Allah be pleased with him) inquired about him, and he was praised well. So Sayyiduna Umar (may Allah be pleased with him) said to him: "Then his wala' (patronage) is yours, and his maintenance is upon us from the public treasury (Bayt al-Mal)."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6468