Shaikh Abdur-Razzaaq al-Abbaad said, “Then he mentioned this mowqoof hadith from Abu Hurairah, may Allaah be pleased with him, “Let whoever meets his brother give him salaam,” you meet one of your brothers on the road, you give salaam to him, and then if you’re both going along together, walking together, and a palm-tree, a tree, a pillar, a car, or anything else comes between you, when you meet up again after this small separation, you give salaam to him, and this is a sunnah many people are heedless of, either because they don’t know it, or they don’t give attention to implementing it.
So he said, “Let whoever meets his brother give him salaam, then if a tree or a wall comes between them after which they meet [again], then give him salaam.”
A proof of this is the Prophet’s ﷺ statement where he said, “Spread the salaam among each other,” i.e., let the salaam be widespread amongst you even after the smallest separation, even after the smallest parting, even if you were only separated from your brother for a short moment, a tree [for example] came between you both, or a pillar, a pole, a car, an animal, or anything else—then give salaam, spread salaam.
Namely, be eager to spread salaam among your brothers even if the gap between you wasn’t a long one, even if you only went away for a short moment and then returned, as is mentioned in the hadith of the man who didn’t perform his prayer correctly, he prayed and then came to where the Prophet ﷺ was sitting and gave salaam, and the Prophet ﷺ said to him, “Go back and pray because you haven’t prayed,” so he went away and prayed, close to them in the mosque, then came back [again] and gave salaam, the Prophet ﷺ said to him, “Go back and pray because you haven’t prayed,” so he went and prayed again close by them, then came back and gave salaam. So giving salaam is something required even if the gap is a short one ...
And I recall being next to Shaikh al-Albaani, may Allaah have mercy on him, here in Medinah when I was young, walking next to him, only me and him, a pillar came between him and I and after we passed it he looked at me smiling and said, “As-Salaamu alaikum,” I said, “Wa alaikum salaam,” then he asked me, “Why did I give you salaam?”—I never knew this hadith and hadn’t come across it before—[so he asked], “Why did I give you salaam?” So I smiled and said, “The salaam is something good.” And then he mentioned this hadith to me, so the first time I got to know this hadith was through the Shaikh, may Allaah have mercy on him.
So the point is a Muslim should be keen to spread the salaam even if the gap is short or minor so as to gain these great rewards and good deeds.”