2 Thessalonians 2:15: "Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle."
According to Franklin Senters, "Stand fast means to act like a mannequin on your beliefs. Don’t be persuaded by the latest and greatest thing that comes along. Stand solid on the word of God. Don’t let someone with a new interpretation of the scripture entice you to believe something different than what is really there in the Word of God. It also means keep standing. Don’t quit."