Al-Kāfi - The Book of Wills

Chapter: The Matters Permissible in Endowment, Charity, Gift, Present, Providing Conditional Housing and Matters Permissible or otherwise for a Child and others َهْزِيَارَ قَالَ قُلْتُ رَوَى بَعْضُ ٠َوَالِيكَ عَنْ آبَائِكَ (عَلَيْهِ٠) أَنَّ كُلَّ وَقْفٍ إِلَى وَقْتٍ ٠ٍ فَهُوَ وَاجِبٌ عَلَى الْوَرَثَةِ وَكُلَّ وَقْفٍ إِلَى غَيْرِ وَقْتٍ ٠َجْهُولٌ بَاطِلٌ ٠َرْدُودٌ عَلَى الْوَرَثَةِ وَأَنْتَ أَعْلَ٠ُ بِقَوْلِ آبَائِكَ فَكَتَبَ (عَلَيْهِ السَّلا٠) هُوَ عِنْدِي كَذَا.

You know best the words of your ancestors.’ He (the Imam) (a.s.), wrote the answer that said, ‘It, with me, is as such.’” (Apparently he (the Imam) left it unexplained.) صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (3/61))