Ibn Sirin (may Allah have mercy on him) said that Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him) divided his wealth among his sons during his lifetime; then, after his death, a son was born to him. Sayyiduna Umar (may Allah be pleased with him) met Sayyiduna Abu Bakr (may Allah be pleased with him) and said: I could not sleep last night because of this newborn son of Sa'd, for nothing has been left for him. Abu Bakr (may Allah be pleased with him) said: By Allah, I too could not sleep last night - or as he said - because of him. Come, let us go to Sayyiduna Qays bin Sa'd (may Allah be pleased with him) and speak to him about his brother. So the two of them came to him and spoke to him, and Sayyiduna Qays (may Allah be pleased with him) said: As for what Sa'd has carried out, I will never take it back; but I make you both witnesses that my share is for this brother.
Hadith Referenceالمعجم الكبير للطبراني / باب القاف / 15974