حَدَّثَنِي مَالِكٌ، عَنْ دَاوُدَ بْنِ الْحُصَيْنِ، عَنْ أَبِي غَطَفَانَ بْنِ طَرِيفٍ الْمُرِّيِّ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، قَالَ مَنْ وَهَبَ هِبَةً لِصِلَةِ رَحِمٍ أَوْ عَلَى وَجْهِ صَدَقَةٍ فَإِنَّهُ لاَ يَرْجِعُ فِيهَا وَمَنْ وَهَبَ هِبَةً يَرَى أَنَّهُ إِنَّمَا أَرَادَ بِهَا الثَّوَابَ فَهُوَ عَلَى هِبَتِهِ يَرْجِعُ فِيهَا إِذَا لَمْ يُرْضَ مِنْهَا ‏.‏ قَالَ يَحْيَى سَمِعْتُ مَالِكًا يَقُولُ الأَمْرُ الْمُجْتَمَعُ عَلَيْهِ عِنْدَنَا أَنَّ الْهِبَةَ إِذَا تَغَيَّرَتْ عِنْدَ الْمَوْهُوبِ لَهُ لِلثَّوَابِ بِزِيَادَةٍ أَوْ نُقْصَانٍ فَإِنَّ عَلَى الْمَوْهُوبِ لَهُ أَنْ يُعْطِيَ صَاحِبَهَا قِيمَتَهَا يَوْمَ قَبَضَهَا ‏.‏

Malik related to me from Da'ud ibn al-Husayn from Abu Ghatafanibn Tarif al-Muriyi that Umar ibn al-Khattab said, "If someone gives agift to strengthen ties with a relative or as sadaqa, he cannot haveit returned. If some one, however, gives a gift seeking by it favouror reward, he has his gift and can reclaim it if he does not havesatisfaction from it." Yahya said that he heard Malik say,"The generally agreed-on way of doing things in our community is thatif the gift is returned to the one who gave it for recompense, and itsvalue has been either increased or decreased, the one to whom it hasbeen given gives the owner its value on the day he received it." Translation Not Available

Book Ref: Muwatta Imam Malik Book 36 Hadith 1445
Web Ref:  Muwatta Imam Malik Book 36 Hadith 42