Al-Kāfi - Volume 7 > The Legacy Comes from the Share of the One Nearest in Relationship to Him and that the Owner of Ordained Share is more Deserving than those who do not have any Ordained Share
Hadith #2

2- ابْنُ مَحْبُوبٍ عَنْ حَمَّادٍ أَبِي يُوسُفَ الْخَزَّازِ عَنْ سُلَيْمَانَ بْنِ خَالِدٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ كَانَ أَمِيرُ الْمُؤْمِنِينَ (عَلَيْهِ السَّلام) يَقُولُ إِذَا كَانَ وَارِثٌ مِمَّنْ لَهُ فَرِيضَةٌ فَهُوَ أَحَقُّ بِالْمَالِ.

2. Ibn Mahbub from Hammad abu Yusuf al-Khazzaz from Sulayman ibn Khalid who has narrated the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said that ’ Amir al-Mu’minin would say, ‘An heir who has an ordained share is more deserving of the legacy.’”