Alongside “All truth is God’s truth,” we need to say, “All truth exists to display more of God and awaken more love for God.” This means that knowing truth and knowing it as God’s truth is not a virtue until it awakens desire and delight in us for the God of truth. And that desire and delight are not complete until they give rise to words or actions that display the worth of God. That is, we exist to glorify God (1 Corinthians 10:31), and merely knowing a truth to be God’s truth does not glorify him any more than the devil does.
All truth exists to make God known and loved and shown. If it does not have those three effects it is not known rightly and should not be celebrated as a virtue.