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It was narrated that Ibn 'Abbas said: "The Messenger of Allah (ﷺ) said: 'It does not befit us to leave bad examples. The one who takes back his gift is like a dog with its vomit.'"
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا مُحَمَّدُ بْنُ حَاتِمِ بْنِ نُعَيْمٍ، قَالَ حَدَّثَنَا حِبَّانُ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ خَالِدٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لَيْسَ لَنَا مَثَلُ السَّوْءِ الرَّاجِعُ فِي هِبَتِهِ كَالْكَلْبِ فِي قَيْئِهِ " .
sunnah.com