Adam Clarke on 1 Samuel 10:4

And they will salute thee - ושאלו לך לשלום veshaalu lecha leshalom, "And they will inquire of thee concerning peace," i.e., welfare. In the East, if this salutation be given, then the person or persons giving it may be reckoned friends; if the others return it, then there is friendship on both sides. Salaam alicum, Peace to you! is the mode of compellation: Alicum essalaam, To you be peace! is the return. If you give the former and receive not the latter, you may expect hostility. The meaning of the prophet is, When you come to the plain of Tabor, ye shall meet three men; you need not be afraid of them, for they are friends; and they will show this friendship, not only by bidding you good speed, but by giving you two loaves of bread, a provision which you will need for the remaining part of your journey.