The logic of the Lord Jesus is so simple. They were used to complex reasoning, and this would have bowled them over.
Scripture views man as consisting of two parts. Both are essential to his being; both are made in the image of God, though the body is made in that image by analogy. Man cannot be all he was made to be without his body, and therefore death is a strong enemy, and the resurrection is of vital importance. Though the dead in Christ exist for a time without the body in the intermediate state, they cannot remain in that state indefinitely. Their souls must be reunited with their glorified bodies. But the soul is the centre of man’s being, while the body is a vessel which carries it. The soul is the conscious part of us: the part that loves God, worships him, knows him, obeys him. Yes, the body joins in also, but the Spirit of God dwells in the heart, because the spirit of a man within him is the part that relates to God directly, and has fellowship with him.
In emphasising externals, the Pharisees put so much attention on the body, that they almost forgot about the heart, the inner man. They almost treated it as if it did not exist, did not come into the reckoning, was not equally made by God. Is the Lord mindful of one part of the being that he has made, and not concerned about the other part? Of course not, says the Lord. God knows the mystery of all that is within us. To think otherwise is to think like a fool. It is so obvious that every part of us is created and designed by a skilful Creator. Who can fail to appreciate the wonderful subtlety of the affections and their tender feelings? Who does not wonder at the heights and depths of truth conquered by the human mind? We are made to think God’s thoughts after him, and even while on earth we are capable to understanding glorious heavenly truths. We are to love and serve God with every part of our being. But it suited the Pharisees to focus on the visible, and they lost sight of the invisible, the greater part of man. That was no small error.