We are to speak the truth in love. At the same time, Jesus began his ministry by knotting together a whip of cords and driving animals out of the temple (John 2). He did the same thing the week before He was crucified. Though the Bible does not say this, I believe that Jesus probably cleansed the temple every time he came to Jerusalem. So what does God expect from us? How are we to handle open sin?
Jesus preached the same truth over and over again. Yet at the end of his life on earth, his disciples still did not understand. Paul commands Timothy to “preach the Word, be instant in season and out of season; reprove, rebuke, exhort, with all longsuffering and doctrine.”
God loved Israel so much that he sent them prophet after prophet. The message of Isaiah was the same message of Jeremiah, Ezekiel, Daniel, etc. We are commanded to “preach the Word, be instant in season and out, reprove, rebuke, exhort, with all longsuffering and doctrine.”
There are Jews who believe just like I do in the OT, yet they reject the entire NT and do not trust in Jesus as the Messiah. Some of few of those Jews actually believe the NT to be good history. They just reject Jesus as the Messiah and believe the NT is not inspired.
Yet Jesus still says “I am the Way the Truth and the Life. No man comes to the Father, except through Me.” John 14:6