When one of you meets his brother, he should salute him, then if he meets him again after a tree, wall or stone has come between them, he should also salute him. Mu'awiyah said: 'Abd al-Wahhab b. Bakht transmitted a similar tradition to me from Abu al-Zinad, from al-A'raj, from Abu Hurairah, from the Messenger of Allah ﷺ.  

إِذَا لَقِيَ أَحَدُكُمْ أَخَاهُ فَلْيُسَلِّمْ عَلَيْهِ فَإِنْ حَالَتْ بَيْنَهُمَا شَجَرَةٌ أَوْ جِدَارٌ أَوْ حَجَرٌ ثُمَّ لَقِيَهُ فَلْيُسَلِّمْ عَلَيْهِ أَيْضًا قَالَ مُعَاوِيَةُ وَحَدَّثَنِي عَبْدُ الْوَهَّابِ بْنُ بُخْتٍ عَنْ أَبِي الزِّنَادِ عَنِ الأَعْرَجِ عَنْ أَبِي هُرَيْرَةَ عَنْ رَسُولِ اللَّهِ ﷺ مِثْلَهُ سَوَاءً