You can bow your head but still lift up your eyes. But this man bent over in the knowledge of his own uncleanness and would not lift up his face or his eyes unto God. In humility he stands afar off in the consciousness of his unworthiness. First of all, then, he stood in humility. Secondly, he stood in contrition.
Contrition is the opposite of carnal indifference to one's sins.
It is a self-slaying and sorrow after God in the confession, I have sinned. This man has no indifference before God. He asks for God to be merciful to him. That is contrition. He beats upon his breast.