There were and are also false teachers. Isaiah 28:9-10 even makes fun of them by penning their words to their followers. The wording was repetitious, almost sonorous and displays the idea of the ludicrous nature ofthe Pharisee's teaching. This is reiterated in Matthew 23:13-29, in Jesus' sermon about various woes that will come upon the Pharisees and their followers. In fact in looking at Matthew 5:1-48, in which Jesus instructs His apostles about the meek and the poor in spirit and those that mourn, etc. etc., in the Sermon on the Mount, as well as teaching them about divorce and praying and fasting, Jesus shows His followers how to look out for false teachers and to be wary of what they are teaching. Mark 12:35 also displays the scribes as false teachers, because of their interpretation of who the Messiah is. And there was a warning about being a false teacher, witout even knowing that one is a false teacher, given in James 3:1 which says that one shouldn't seek to be a teacher because the responsibility is stricter than for those that are not teachers. That doesn't mean tht people who are students are immune to the responsibility of spreading the gospel. No, the responsibility is there as well, according to Galatians 6:6. Hence all of God's children have the responsibility not to spread things that are not the truth about God's Word.