Norman Grubb emphasizes the importance of moving from mere mental understanding to experiential knowledge in our spiritual journey. He highlights the challenge of transitioning from head knowledge to heart transformation, stressing the need for a deep, tested, and proven experience of God's truth before we can effectively lead others into it. Grubb warns against stagnation in spiritual growth, urging believers to mature from consuming 'milk' to embracing 'strong meat' by exercising their spiritual senses to discern good and evil, as mentioned in Hebrews 5:12-14.

May I say this—for I shall repeat it later on—it comes somewhat into that same category of acts and ways. It’s one thing to experience. It’s another thing to be able to expound your experience and, lead other people into it. It’s one thing for ourselves to see something even in a small way mentally. But to get it experientially is very much something! It’s very much two feet further down, to come from head to heart. It takes a long time to go those two feet sometimes. We love to think it’s in the heart when it’s only in the head. And even then, it takes a much longer time to have such a clarification of knowledge in the spirit, worked out in experience, tested, tried, proven, so we can both expound to others and lead them into what’s been given to us. Now that’s what it is to be teachers as God’s Word says in Hebrews 5:12-14. Now when you ought to be teachers beware lest you have to be taught yourselves again, and beware lest you have to be drinking milk when you ought to be eating meat. And he says, “Strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.” That’s a strange phrase. It shows how much deeper everything is than we think. Karuizawa Japan Conference of 1954