you're quoting from the King James
there's been quite some development in the English language from when the KJV was written, so the original meaning of 'within you' when the translators chose that phrase has changed somewhat from the tense in which the reader would have understood it in the 18th Century; and from that have been derived common heresies which hold that like the occultic eastern religions, that the answers lie within one's own heart
this is an untruth, a satanic lie, and a repudiation of the teaching of Christ that one must have revelatory insight imputed to them by the Holy Spirit - the words of The Lord in this moment simply meaning 'the kingdom of heaven is already amongst you' pointing to Himself and rebuking the unbelieving Pharisees whom he addressed
just look at the following verses which give this phrase context
/thread