There is the Gift of Knowledge for our sanctification and there is the Gift of Word of Knowledge for the service of others. When Jesus was in conversation with the Samaritan woman at the well, Jesus had a Word of Knowledge about her marital situation. What the Spirit revealed to Jesus was not a word of judgment but a word of confirmation  to what was stirring in her heart. The proof of the Word of Knowledge lies in the other person. We are only called to be the messenger of the Lord to the person. Not every thought is of the Lord. It must be tested, but not stifled. Be open to the move of the Spirit and learn what is of God and what is not. Be not afraid to speak the Word given you.