"For by your words you will be justified, and by your words you will be condemned” (Matthew 12:37).
Federal Visionists love this verse because they think that we will be justified by our words, which they use to support two of their most nefarious doctrines: 1) justification apart from faith; and 2) future justification. Obviously, these Pelagian doctrines bear little resemblance to the solas.
The Reformed faith has always insisted that justification can only refer to the forensic declaration of righteousness that is received by faith alone. Our words have nothing to do with justification. This is simply works-righteousness repackaged as the gospel, which is no gospel at all.
Furthermore, no Reformed theologian has ever held to a “future justification” or a so-called “future-aspect of justification.” The only kind of justification that is future is for the elect who are not yet justified.
When Jesus said, “by your words you will be justified,” there is no reason to assume that he is meant spoken words. Spoken words would be a work, and we know that “a man is justified by faith apart from works” (Romans 3:28). Jesus must be referring to words of the mind, or thoughts. As soon as you can think the thought, “I believe in the imputation of the active obedience of Christ” then you have faith and you are justified by this faith that is alone. Praise God for sola fide!