RENEWING YOUR GREETING H 872 "When you meet a brother greet him. Then if you are separated by a tree, a wall or a boulder, you should greet each other again when you meet." R 872 Abu Daud with a chain up to Abu Hurairah who related that the Prophet, praise and peace be upon him, said this.
860- وعنه ، عن رسول الله صلى الله عليه وآله وسلم ، قَالَ : "إِذَا لَقِيَ أَحَدُكُمْ أخَاهُ فَلْيُسَلِّمْ عَلَيْهِ ، فَإنْ حَالَتْ بَيْنَهُمَا شَجَرَةٌ ، أَوْ جِدَارٌ ، أَوْ حَجَرٌ ، ثُمَّ لَقِيَهُ ، فَلْيُسَلِّمْ عَلَيْهِ" رواه أَبُو داود .