Jesus only told us one thing that could ever render his word, his truth, ineffective. Most would readily say, "Well it must be sin" or "It must be disobedience." No, Jesus said the one thing that could render his truth ineffective is the traditions of men (Mark 7:13).
Every church has been based on the traditions of men for nearly 2,000 years. The entire church system is based on the traditions of men. Men took what Jesus said "stops the truth of God" & used it to create what is supposed to be the main place where people get the truth of God. That is like designing a race track with a brick wall at the starting line. Either people go nowhere or they crash. God is with His people whether there is a brick wall or not so people can connect with God & learn from Him no matter where they are or what they are doing. Still every building that people go to supposedly get closer to God in is already stopping at least some truth of God based on their mere existence.
Jesus wants to teach you all truth but your belief in traditions of men stop His truth from clinging to your heart. Even if you don't rely on or believe in them very much the fact that they are practiced in your presence stops the truth of God & gives you certain perceptions about yourself, others, & God.