Al-Adab Al-Mufrad, Book 42, Hadith 1015 (English) ⓘ

Abu Hurayra said, "The most miserly of people is the person who is miserly with the greeting. The one who is cheated of good is the one who does not return it. if a tree comes between you and your brother, and you are able to be the first to begin the greeting before the other person, then do it."

حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، قَالَ‏:‏ حَدَّثَنَا زُهَيْرٌ، قَالَ‏:‏ حَدَّثَنَا كِنَانَةُ مَوْلَى صَفِيَّةَ، عَنْ أَبِي هُرَيْرَةَ قَالَ‏:‏ أَبْخَلُ النَّاسِ مَنْ بَخِلَ بِالسَّلاَمِ، وَالْمَغْبُونُ مَنْ لَمْ يَرُدَّهُ، وَإِنْ حَالَتْ بَيْنَكَ وَبَيْنَ أَخِيكَ شَجَرَةٌ، فَإِنِ اسْتَطَعْتَ أَنْ تَبْدَأَهُ بِالسَّلامِ لا يَبْدَأُكَ فَافْعَلْ‏.‏