وَعَنْ عَائِشَةَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «تَهَادُوا فَإِنَّ الْهَدِيَّةَ تُذْهِبُ الضَّغَائِنَ» . رَوَاهُ

‘A’isha reported the Prophet as saying, “Give presents to one another, for a present removes grudges.”

…transmitted it. (Mirqat, 3:380 says that Tirmidhi is the source in which this tradition is found. I have looked for it with the help of the Concordance, but have been unable to find it.