«أيما رجل أعمر رجلا عمرى له ولعقبه فهي له ولمن يرثه من عقبه موروثة»
The Prophet (peace and blessings be upon him) said:
"Any man who gives another man something as an umra (a lifelong gift), saying that it is for you and your descendants, then that thing belongs to him and to his heirs from among his descendants, and will be divided among them as inheritance."
Hadith Referenceصحیح الجامع الصغیر / حرف الألف / 2715