Philoxenus of Mabbug

It is the same now with us who are baptized: neither the wetness of the water in which we are baptized nor the oiliness of the oil with which we are anointed remain with us after our death. But the Holy Spirit, who is mingled in our souls and bodies through the oil and the water, does remain with us, both in this life and after our death.

The Holy Spirit is our true baptism, and for this reason we remain always baptized, for he is in us always, and nothing can deprive us of our baptism apart from the denial of God and consorting with demons. In such cases the Holy Spirit really does depart, because he cannot agree to remain in a place where Satan dwells. “For what fellowship does Christ have with Satan or the believer with the unbeliever, or God’s temple with that of demons?”