God dwells in a soul not in grace giving it being and holding it in existence. This soul is not able to receive light from the Lord, however. St. Teresa of Jesus says these souls are “in a dark prison” and that they cannot do anything good nor can they merit anything for themselves. She exhorts us to have pity on these unfortunate souls and to think about our own past sins and the time when we were in this sad condition. Since the Lord had mercy on us, we should also desire that He have mercy on them.
St. Teresa wants us to give alms by praying for those souls in mortal sin:
“Let us take special care, Sisters, to beg this mercy of Him and not be careless, for it is a most generous alms to pray for those who are in mortal sin.” (Interior Castle VII, 1, 4)
A soul in mortal sin is “bound hands and feet” “dying of hunger” because he cannot take hold of the food that is set before him and eat. In truth this soul has a great disgust for the food. But we should not just stand by and let this soul die for the death is an eternal one.
St. Teresa continues in The Interior Castle to say that our prayers can loosen the bonds of souls that are in this sad state:
“For the love of God I ask you always to remember in your prayers souls in mortal sin.” (Interior Castle, VII, 1,4)
This is how Carmelites are to save souls – by praying for them, for to pray is to give. We should beg God’s mercy on them so that the darkness that covers their souls will be lifted and they will receive light.