“I thank you, Father, Lord of heaven and earth, that you have hidden these things from the wise and understanding and revealed them to little children; yes, Father, for such was your gracious will.” (Luke 10:21)
Believing something because you have heard a reliable testimony is not necessarily the same mental and spiritual experience as believing something because you have tasted or apprehended its spiritual beauty.
When you believe merely on the basis of a testimony, you might assent to the truth without delighting in it or seeing it as spiritually beautiful. But when you believe because you have had a spiritual “taste” or “apprehension” of spiritual beauty, then the faith itself is permeated by this taste of spiritual beauty.
Charles Hodge says, “We may believe on the testimony of those in whose veracity and judgment we confide, that a man of whom we know nothing has great moral excellence. But if we see for ourselves the exhibition of his excellence, we believe for other reasons, and in a different way.”
What makes faith saving faith is this “different way” of believing that comes from a different (not alternative, or contradictory) way of apprehending or tasting the reality behind the testimony we affirm. This different way is what Hodge calls a “spiritual apprehension of the truth.” He says, “It is a faith which rests upon the manifestation by the Holy Spirit of the excellence, beauty, and suitableness of the truth. . . . It arises from a spiritual apprehension of the truth, or from the testimony of the Spirit with and by the truth in our hearts.”
To illustrate this kind of spiritual apprehension, Hodge cites Luke 10:21, “In that same hour [Jesus] rejoiced in the Holy Spirit and said, ‘I thank you, Father, Lord of heaven and earth, that you have hidden these things from the wise and understanding and revealed them to little children; yes, Father, for such was your gracious will.’”
In other words, the truth about Jesus and his ministry and the kingdom of God was seen externally by some; but to “little children,” God revealed it. This revelation enabled that spiritual apprehension and taste that moves the heart to embrace and savor the reality, not just think that it is true.