A.T. Robertson Commentary Luke 17:21

"neither shall they say, Lo, here! or, There! for lo, the kingdom of God is within you." — Luke 17:21 (ASV)

Within you (εντος υμων). This is the obvious, and, as I think, the necessary meaning of εντος. The examples cited of the use of εντος in Xenophon and Plato where εντος means "among" do not bear that out when investigated. Field (Ot. Norv.) "contends that there is no clear instance of εντος in the sense of among" (Bruce), and rightly so. What Jesus says to the Pharisees is that they, as others, are to look for the kingdom of God within themselves, not in outward displays and supernatural manifestations. It is not a localized display "Here" or "There." It is in this sense that in Lu 11:20 Jesus spoke of the kingdom of God as "come upon you" (εφθασεν εφ' υμας), speaking to Pharisees. The only other instance of εντος in the N.T. (Matthew 23:26) necessarily means "within" ("the inside of the cup"). There is, beside, the use of εντος meaning "within" in the Oxyrhynchus Papyrus saying of Jesus of the Third Century (Deissmann, Light from the Ancient East, p. 426) which is interesting: "The kingdom of heaven is within you" (εντος υμων as here in Lu 17:21).