“What mars the simplicity of the childlike faith which Jesus commends is not an admixture of knowledge, but an admixture of self-trust. To receive the kingdom as a little child is to receive it as a free gift without seeking in the slightest measure to earn it for one’s self.
There is a rebuke here for any attempt to earn salvation by one’s own character, by one’s own obedience to God’s commands, by one’s own establishment in one’s life of the principles of Jesus; but there is no rebuke whatever for an intelligent faith that is founded upon the facts.
The childlike simplicity of faith is marred sometimes by ignorance, but never by knowledge; it will never be marred—and never has been marred in the lives of the great theologians—by the blessed knowledge of God and of the Saviour Jesus Christ which is contained in the Word of God.
Without that knowledge we might be tempted to trust partly in ourselves; but with it we trust wholly to God. The more we know of God, the more unreservedly we trust Him; the greater be our progress in theology, the simpler and more childlike will be our faith.”
–J. Gresham Machen, What is Faith? (Carlisle, PA: Banner of Truth, 1925/1991), 95.