“We are the body of Christ,” says St Paul, “and each of us is one of its members” (cf. 1 Corinthians 12:27). And elsewhere he says, ” You are one body and one spirit, even as you have been called” (Ephesians 4:4). For “as the body without the spirit is dead” (James 2:26) and insensate, so if you have been deadened by the passions through neglecting the commandments after your baptism the Holy Spirit and the grace of Christ cease to operate in you and to enlighten you; for though you possess the Spirit, since you have faith and have been regenerated through baptism, yet the Spirit is quiescent and inactive within you because of the deadness of your soul.
Although the soul is one and the members of the body are many, the soul sustains them all, giving life and movement to those that can be animated. Should some of them have withered because of some disease and become as if dead and inert, yet they are still sustained by the soul, even in their lifeless and insensate state.
Similarly, the Spirit of Christ is present with integral wholeness in all who are members of Christ, activating and generating life in all capable of participating in it; and in His compassion He still sustains even those who through some weakness do not actively participate in the life of the Spirit. In this way each of the faithful participates, by virtue of his faith, in adoption to sonship through the Spirit; but should he grow negligent and fail to sustain his faith he will become inert and benighted, deprived of Christ’s life and light. Such is the state of each of the faithful who, though a member of Christ and possessing the Spirit of Christ, fails to activate this Spirit within himself and so is stagnant, incapable of participating positively in the life of grace.
~St Gregory of Sinai.