The ruling on returning the salam by saying: (And upon you)

Question : A person greets someone by saying, "As-salamu alaykum," and he replies, "Wa alaykum." Do I return the salam to him and support him?

Answer : No, there is no need. If he says "Wa alaykum," that is well known, because it is permissible to omit the predicate and omit the subject. They said, "Salam," and he said, "Salam." It is not that the subject was omitted; the predicate was omitted. No, but it is not recommended, because I fear that if I say "Wa alaykum," the Muslim might have something in his heart. Perhaps, if he has knowledge, he would say, "Come, am I a Muslim?" Certainly, the matter is that a person is reassured by his companion. So there is no harm.